Re: N600 master cylinder check valves

Greg Prentice · Post by **Greg Prentice** » Sat Aug 04, 2018 8:05 am

Hello all. Just got my 71 N600 on the road. All ok for the first few test drives – but just today while driving found both front brakes becoming more and more stuck on. Rears were fine. Got home and let cool down. After an hour of cooling found both front wheels free to turn – and all ok at the wheel cylinders. Thinking since both front brakes stuck on it was not likely a case of jamming calipers or similar. Thinking something in the master cylinder or booster…? The master cylinder check valves have different part numbers for front and rear circuit. Does anyone know how to tell which is which? And why they are different ? The check valve seat is also a different part number for front and rear. My MC has a rubber seat with notches on sides for one circuit and steel washer for the other circuit…??? Would something sticking in the booster cause brake pressure to remain when the brake pedal is released? Thank You. Greg Prentice Toromont Power Systems 905 488 2571
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Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7 www.toromont.com (416)667-5511.
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Mark P Hatten · Post by **Mark P Hatten** » Sat Aug 04, 2018 11:48 am

This same incident happened, we had to get the booster rebuilt @ karps power brake

Works fine now.

--
Sent from Hotmail Email App for Android

Saturday, 04 August 2018, 03:05PM -07:00 from Greg Prentice GPrentice@... [anzhonda600owners]
anzhonda600owners@yahoogroups.com:

Hello all.

Just got my 71 N600 on the road.

All ok for the first few test drives but just today while driving found both front brakes becoming more and more stuck on. Rears were fine.
Got home and let cool down.
After an hour of cooling found both front wheels free to turn and all ok at the wheel cylinders.

Thinking since both front brakes stuck on it was not likely a case of jamming calipers or similar.
Thinking something in the master cylinder or booster ?

The master cylinder check valves have different part numbers for front and rear circuit.
Does anyone know how to tell which is which? And why they are different ?
The check valve seat is also a different part number for front and rear. My MC has a rubber seat with notches on sides for one circuit and steel washer for the other circuit ???

Would something sticking in the booster cause brake pressure to remain when the brake pedal is released?

Thank You.

Greg Prentice
Toromont Power Systems
905 488 2571

This e-mail and any attachments may be confidential or legally privileged. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of
this information is strictly prohibited. Please notify us immediately by email at
corpmail@... or by telephone (collect if necessary). Please delete this email and destroy any copies. Thank you for your cooperation.
Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7
www.toromont.com (416)667-5511.

Ce courriel, ainsi que tous les fichiers joints, sont consid?r?s comme confidentiels ou juridiquement privil?gi?s. Si vous n'?tes pas le destinataire d?sign? du pr?sent message, soyez avis? que toute divulgation, copie,
distribution ou action se fondant sur le contenu est strictement interdite. Veuillez nous en aviser imm?diatement par courriel ? l'adresse
corpmail@... ou par t?l?phone (? frais vir?s si n?cessaire). Veuillez effacer ce courriel et toute copie ?ventuelle. Merci pour votre coop?ration.

Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7
www.toromont.com (416)667-5511.

Miles Chappell · Post by **Miles Chappell** » Sat Aug 04, 2018 6:17 pm

It's not a master cylinder problem, but the check valves are different only because one has a notch in the top. The flat ones were obsoleted many years ago and recently I hear the notched ones are discontinued. Since the ones with the 533 center number fit Honda S800 you might find them in England or from Michael Ortmann in Germany. The problem will be your brake booster, the reaction port piston is aluminum and is in aluminum body. They get seized in the bore. I used to rebuild boosters, but have not for years since parts are impossible. If you are lucky you could clean the tiny piston and have it work but likely you will need more work than that. Miles

heedo · Post by **heedo** » Sat Aug 04, 2018 8:23 pm

What I've found if the front brakes stick is the booster is not returning to the non pushed state. Disassemble the booster, and polish the rod where it goes thru the big diaphragm, it will be stuck in it there.. that will fix it

Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: "Mark P Hatten mphatten@... [anzhonda600owners]" Date: 8/4/18 9:48 PM (GMT-05:00) To: anzhonda600owners@yahoogroups.com Subject: Re: [anzhonda600owners] N600 master cylinder check valves

This same incident happened, we had to get the booster rebuilt @ karps power brake
Works fine now. --
Sent from Hotmail Email App for Android Saturday, 04 August 2018, 03:05PM -07:00 from Greg Prentice GPrentice@... [anzhonda600owners] anzhonda600owners@yahoogroups.com:

Hello all. Just got my 71 N600 on the road. All ok for the first few test drives but just today while driving found both front brakes becoming more and more stuck on. Rears were fine. Got home and let cool down. After an hour of cooling found both front wheels free to turn and all ok at the wheel cylinders. Thinking since both front brakes stuck on it was not likely a case of jamming calipers or similar. Thinking something in the master cylinder or booster ? The master cylinder check valves have different part numbers for front and rear circuit. Does anyone know how to tell which is which? And why they are different ? The check valve seat is also a different part number for front and rear. My MC has a rubber seat with notches on sides for one circuit and steel washer for the other circuit ??? Would something sticking in the booster cause brake pressure to remain when the brake pedal is released? Thank You. Greg Prentice Toromont Power Systems 905 488 2571
This e-mail and any attachments may be confidential or legally privileged. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. Please notify us immediately by email at corpmail@... or by telephone (collect if necessary). Please delete this email and destroy any copies. Thank you for your cooperation.
Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7 www.toromont.com (416)667-5511.
Ce courriel, ainsi que tous les fichiers joints, sont consid?r?s comme confidentiels ou juridiquement privil?gi?s. Si vous n'?tes pas le destinataire d?sign? du pr?sent message, soyez avis? que toute divulgation, copie, distribution ou action se fondant sur le contenu est strictement interdite. Veuillez nous en aviser imm?diatement par courriel ? l'adresse corpmail@... ou par t?l?phone (? frais vir?s si n?cessaire). Veuillez effacer ce courriel et toute copie ?ventuelle. Merci pour votre coop?ration.
Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7 www.toromont.com (416)667-5511.

Posted by: Mark P Hatten Reply via web post mphatten@...?subject=Re%3A%20%5Banzhonda600owners%5D%20N600%20master%20cylinder%20check%20valves anzhonda600owners@yahoogroups.com?subject=Re%3A%20%5Banzhonda600owners%5D%20N600%20master%20cylinder%20check%20valves Start a New Topic Messages in this topic (2)

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Bill · Post by **Bill** » Sun Aug 05, 2018 1:24 am

Attachments :

Booster piston warn2b.jpg

The booster cylinder piston pushes fluid through the piston to the calipers and releases when the piston release pin is pushed in far enough to release the fluid. It may be that there is something blocking the flow or restricting the pin movement. From: anzhonda600owners@yahoogroups.com [mailto: anzhonda600owners@yahoogroups.com ]
Sent: Sunday, August 05, 2018 3:23 AM
To: anzhonda600owners@yahoogroups.com
Subject: Re: [anzhonda600owners] N600 master cylinder check valves What I've found if the front brakes stick is the booster is not returning to the non pushed state. Disassemble the booster, and polish the rod where it goes thru the big diaphragm, it will be stuck in it there.. that will fix it Sent from my Verizon, Samsung Galaxy smartphone -------- Original message -------- From: "Mark P Hatten mphatten@... [anzhonda600owners]" < anzhonda600owners@yahoogroups.com > Date: 8/4/18 9:48 PM (GMT-05:00) To: anzhonda600owners@yahoogroups.com Subject: Re: [anzhonda600owners] N600 master cylinder check valves This same incident happened, we had to get the booster rebuilt @ karps power brake
Works fine now.
--
Sent from Hotmail Email App for Android Saturday, 04 August 2018, 03:05PM -07:00 from Greg Prentice GPrentice@... [anzhonda600owners] anzhonda600owners@yahoogroups.com:

Hello all. Just got my 71 N600 on the road. All ok for the first few test drives – but just today while driving found both front brakes becoming more and more stuck on. Rears were fine. Got home and let cool down. After an hour of cooling found both front wheels free to turn – and all ok at the wheel cylinders. Thinking since both front brakes stuck on it was not likely a case of jamming calipers or similar. Thinking something in the master cylinder or booster…? The master cylinder check valves have different part numbers for front and rear circuit. Does anyone know how to tell which is which? And why they are different ? The check valve seat is also a different part number for front and rear. My MC has a rubber seat with notches on sides for one circuit and steel washer for the other circuit…??? Would something sticking in the booster cause brake pressure to remain when the brake pedal is released? Thank You. Greg Prentice Toromont Power Systems 905 488 2571
This e-mail and any attachments may be confidential or legally privileged. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. Please notify us immediately by email at corpmail@... or by telephone (collect if necessary). Please delete this email and destroy any copies. Thank you for your cooperation.
Toromont Industries Ltd., 3131 Highway 7 West, Concord , ON , L4K 1B7 www.toromont.com (416)667-5511.
Ce courriel, ainsi que tous les fichiers joints, sont consid?r?s comme confidentiels ou juridiquement privil?gi?s. Si vous n'?tes pas le destinataire d?sign? du pr?sent message, soyez avis? que toute divulgation, copie, distribution ou action se fondant sur le contenu est strictement interdite. Veuillez nous en aviser imm?diatement par courriel ? l'adresse corpmail@... ou par t?l?phone (? frais vir?s si n?cessaire). Veuillez effacer ce courriel et toute copie ?ventuelle. Merci pour votre coop?ration.
Toromont Industries Ltd., 3131 Highway 7 West, Concord , ON , L4K 1B7 www.toromont.com (416)667-5511. Posted by: Mark P Hatten < mphatten@... > Reply via web post • mphatten@...?subject=Re%3A%20%5Banzhonda600owners%5D%20N600%20master%20cylinder%20check%20valves • anzhonda600owners@yahoogroups.com?subject=Re%3A%20%5Banzhonda600owners%5D%20N600%20master%20cylinder%20check%20valves • Start a New Topic • Messages in this topic (2)

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D and K Grandinett · Post by **D and K Grandinett** » Mon Aug 06, 2018 10:31 am

We've also had the same binding brake experience. We diagnosed our problem by cracking the tube nut at the front brake outlet of the Master Cylinder to relieve the pressure in the primary circuit to the remote Booster. We actually had to perform that procedure just to make it home a couple of times, but it did confirm that the issue had to do with a blocked or stuck MC check valve. I'd try this pressure relief technique just to see if it temporarily resolves your issue.
I understand that these front and rear check valves are allegedly different, but frankly in my case they appear identical so I can't tell you how to identify one vs the other. Disassembling and carefully cleaning both check valves and a thorough purge bleed of the MC and front brake hydraulic circuit finally resolved our issue. Apparently the very small orifices in these check valves are very sensitive to any dirt or foreign material (including any material coming from old or deteriorating supply lines from the reservoir which also should be checked and replaced if necessary).
My suggestion would be to consider replacing the reservoir lines if they're showing any signs of being around just a bit too long, clean the MC, reservoir and check valves in "clean room" conditions and purge whatever's left with a fresh round of virgin brake fluid through the front system.
Your issue may not be the same because those remote boosters are notoriously sensitive as well, but this simple approach may be a place to start. Good luck.

On August 4, 2018 at 6:05 PM "Greg Prentice GPrentice@... [anzhonda600owners]" wrote:

Hello all. Just got my 71 N600 on the road. All ok for the first few test drives – but just today while driving found both front brakes becoming more and more stuck on. Rears were fine.Got home and let cool down.After an hour of cooling found both front wheels free to turn – and all ok at the wheel cylinders. Thinking since both front brakes stuck on it was not likely a case of jamming calipers or similar.Thinking something in the master cylinder or booster…? The master cylinder check valves have different part numbers for front and rear circuit.Does anyone know how to tell which is which? And why they are different ?The check valve seat is also a different part number for front and rear. My MC has a rubber seat with notches on sides for one circuit and steel washer for the other circuit…??? Would something sticking in the booster cause brake pressure to remain when the brake pedal is released? Thank You. Greg PrenticeToromont Power Systems905 488 2571
This e-mail and any attachments may be confidential or legally privileged. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. Please notify us immediately by email at corpmail@... or by telephone (collect if necessary). Please delete this email and destroy any copies. Thank you for your cooperation.
Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7 www.toromont.com (416)667-5511.
Ce courriel, ainsi que tous les fichiers joints, sont considérés comme confidentiels ou juridiquement privilégiés. Si vous n'êtes pas le destinataire désigné du présent message, soyez avisé que toute divulgation, copie, distribution ou action se fondant sur le contenu est strictement interdite. Veuillez nous en aviser immédiatement par courriel á l'adresse corpmail@... ou par téléphone (à frais virés si nécessaire). Veuillez effacer ce courriel et toute copie éventuelle. Merci pour votre coopération.
Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7 www.toromont.com (416)667-5511.

heedo · Post by **heedo** » Mon Aug 06, 2018 1:45 pm

The way to tell where the blockage is ,loosen the front brake lines where the go into the booster. . I'm better it's the booster sticking

Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: "D & K Grandinett grandinett@... [anzhonda600owners]" Date: 8/6/18 8:31 PM (GMT-05:00) To: anzhonda600owners@yahoogroups.com Subject: Re: [anzhonda600owners] N600 master cylinder check valves

We've also had the same binding brake experience. We diagnosed our problem by cracking the tube nut at the front brake outlet of the Master Cylinder to relieve the pressure in the primary circuit to the remote Booster. We actually had to perform that procedure just to make it home a couple of times, but it did confirm that the issue had to do with a blocked or stuck MC check valve. I'd try this pressure relief technique just to see if it temporarily resolves your issue.
I understand that these front and rear check valves are allegedly different, but frankly in my case they appear identical so I can't tell you how to identify one vs the other. Disassembling and carefully cleaning both check valves and a thorough purge bleed of the MC and front brake hydraulic circuit finally resolved our issue. Apparently the very small orifices in these check valves are very sensitive to any dirt or foreign material (including any material coming from old or deteriorating supply lines from the reservoir which also should be checked and replaced if necessary).
My suggestion would be to consider replacing the reservoir lines if they're showing any signs of being around just a bit too long, clean the MC, reservoir and check valves in "clean room" conditions and purge whatever's left with a fresh round of virgin brake fluid through the front system.
Your issue may not be the same because those remote boosters are notoriously sensitive as well, but this simple approach may be a place to start. Good luck.

On August 4, 2018 at 6:05 PM "Greg Prentice GPrentice@... [anzhonda600owners]" wrote:

Hello all. Just got my 71 N600 on the road. All ok for the first few test drives but just today while driving found both front brakes becoming more and more stuck on. Rears were fine.Got home and let cool down.After an hour of cooling found both front wheels free to turn and all ok at the wheel cylinders. Thinking since both front brakes stuck on it was not likely a case of jamming calipers or similar.Thinking something in the master cylinder or booster ? The master cylinder check valves have different part numbers for front and rear c ircuit.Does anyone know how to tell which is which? And why they are different ?The check valve seat is also a different part number for front and rear. My MC has a rubber seat with notches on sides for one circuit and steel washer for the other circuit ??? Would something sticking in the booster cause brake pressure to remain when the brake pedal is released? Thank You. Greg PrenticeToromont Power Systems905 488 2571
This e-mail and any attachment s may be confidential or legally privileged. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. Please notify us immediately by email at corpmail@... or by telephone (collect if necessary). Please delete this email and destroy any copies. Thank you for your cooperation.
Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7 www.toromont.com (416)667-5511.
Ce courriel, ainsi que tous les fichiers joints, sont consid r s comme confidentiels ou juridiquement privil gi s. Si vous n' tes pas le destinataire d sign du pr sent message, soyez avis que toute divulgation, copie, distribution ou action se fondant sur le contenu est strictement interdite. Veuillez nous en aviser imm diatement par courriel l'adresse corpmail@... ou par t l phone ( frais vir s si n cessaire). Veuillez effacer ce courriel et toute copie ventuelle. Merci pour votre coop ration.
Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7 www.toromont.com (416)667-5511.

Greg Prentice · Post by **Greg Prentice** » Tue Aug 07, 2018 12:53 am

Attachments :

Thanks all for your feedback on my brake issue

I disassembled the booster and found brake fluid where it should not have been.
I am going to send the unit to Karps for rebuild.

Thanks.

From: anzhonda600owners@yahoogroups.com [mailto:anzhonda600owners@yahoogroups.com]

Sent: Monday, August 06, 2018 11:45 PM
To: anzhonda600owners@yahoogroups.com
Subject: Re: [anzhonda600owners] N600 master cylinder check valves

The way to tell where the blockage is ,loosen the front brake lines where the go into the booster. . I'm better it's the booster sticking

Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------

From: "D & K Grandinett grandinett@... [anzhonda600owners]"

Date: 8/6/18 8:31 PM (GMT-05:00)

To: anzhonda600owners@yahoogroups.com

Subject: Re: [anzhonda600owners] N600 master cylinder check valves

We've also had the same binding brake experience. We diagnosed our problem by cracking the tube nut at the front brake outlet of the Master Cylinder to relieve the pressure in the primary circuit to the remote Booster. We actually had to perform that procedure
just to make it home a couple of times, but it did confirm that the issue had to do with a blocked or stuck MC check valve. I'd try this pressure relief technique just to see if it temporarily resolves your issue.

I understand that these front and rear check valves are allegedly different, but frankly in my case they appear identical so I can't tell you how to identify one vs the other. Disassembling and carefully cleaning both check valves and a thorough purge bleed
of the MC and front brake hydraulic circuit finally resolved our issue. Apparently the very small orifices in these check valves are very sensitive to any dirt or foreign material (including any material coming from old or deteriorating supply lines from the
reservoir which also should be checked and replaced if necessary).

My suggestion would be to consider replacing the reservoir lines if they're showing any signs of being around just a bit too long, clean the MC, reservoir and check valves in "clean room" conditions and purge whatever's left with a fresh round of virgin
brake fluid through the front system.

Your issue may not be the same because those remote boosters are notoriously sensitive as well, but this simple approach may be a place to start. Good luck.

On August 4, 2018 at 6:05 PM "Greg Prentice GPrentice@... [anzhonda600owners]" wrote:

Hello all.

Just got my 71 N600 on the road.

All ok for the first few test drives but just today while driving found both front brakes becoming more and more stuck on. Rears were fine.
Got home and let cool down.
After an hour of cooling found both front wheels free to turn and all ok at the wheel cylinders.

Thinking since both front brakes stuck on it was not likely a case of jamming calipers or similar.
Thinking something in the master cylinder or booster ?

The master cylinder check valves have different part numbers for front and rear c ircuit.
Does anyone know how to tell which is which? And why they are different ?
The check valve seat is also a different part number for front and rear. My MC has a rubber seat with notches on sides for one circuit and steel washer for the other circuit ???

Would something sticking in the booster cause brake pressure to remain when the brake pedal is released?

Thank You.

Greg Prentice
Toromont Power Systems
905 488 2571

This e-mail and any attachment s may be confidential or legally privileged. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance
on the contents of this information is strictly prohibited. Please notify us immediately by email at
corpmail@... or by telephone (collect if necessary). Please delete this email and destroy any copies. Thank you for your cooperation.
Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7
www.toromont.com (416)667-5511.

Ce courriel, ainsi que tous les fichiers joints, sont consid r s comme confidentiels ou juridiquement privil gi s. Si vous n' tes pas le destinataire d sign du pr sent message, soyez avis que toute
divulgation, copie, distribution ou action se fondant sur le contenu est strictement interdite. Veuillez nous en aviser imm diatement par courriel l'adresse
corpmail@... ou par t l phone ( frais vir s si n cessaire). Veuillez effacer ce courriel et toute copie ventuelle. Merci pour votre coop ration.

Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7
www.toromont.com (416)667-5511.

D and K Grandinett · Post by **D and K Grandinett** » Tue Aug 07, 2018 12:53 am

On the booster for just a moment-- I rebuilt the little monster a couple of times primarily to resolve pedal effort issues without much success until I finally realized that the kits I was using did not include THE key O-ring where the Piston Rod goes through the Diaphragm Plate. I don't know why my kits didn't include that part, but my O-Ring seal was severely distorted, had caused the rod to contact the Plate (with subsequent scoring) and was evidently the mysterious source of "consumed" brake fluid.
There was also a second O-Ring required for a satisfactory rebuild missing from the kit-- just a heads-up for those who might believe the kits include everything they might need to do it correctly.
You may be right about the booster, but my dragging brake issue was clearly caused by a blocked or stuck MC check valve.On August 6, 2018 at 11:45 PM "heedo heedo@... [anzhonda600owners]" wrote:

The way to tell where the blockage is ,loosen the front brake lines where the go into the booster. . I'm better it's the booster sticking

Sent from my Verizon, Samsung Galaxy smartphone
-------- Original message --------From: "D & K Grandinett grandinett@... [anzhonda600owners]" Date: 8/6/18 8:31 PM (GMT-05:00)To: anzhonda600owners@yahoogroups.comSubject: Re: [anzhonda600owners] N600 master cylinder check valves

We've also had the same binding brake experience. We diagnosed our problem by cracking the tube nut at the front brake outlet of the Master Cylinder to relieve the pressure in the primary circuit to the remote Booster. We actually had to perform that procedure just to make it home a couple of times, but it did confirm that the issue had to do with a blocked or stuck MC check valve. I'd try this pressure relief technique just to see if it temporarily resolves your issue.
I understand that these front and rear check valves are allegedly different, but frankly in my case they appear identical so I can't tell you how to identify one vs the other. Disassembling and carefully cleaning both check valves and a thorough purge bleed of the MC and front brake hydraulic circuit finally resolved our issue. Apparently the very small orifices in these check valves are very sensitive to any dirt or foreign material (including any material coming from old or deteriorating supply lines from the reservoir which also should be checked and replaced if necessary).
My suggestion would be to consider replacing the reservoir lines if they're showing any signs of being around just a bit too long, clean the MC, reservoir and check valves in "clean room" conditions and purge whatever's left with a fresh round of virgin brake fluid through the front system.
Your issue may not be the same because those remote boosters are notoriously sensitive as well, but this simple approach may be a place to start. Good luck.

On August 4, 2018 at 6:05 PM "Greg Prentice GPrentice@... [anzhonda600owners]" wrote:

Hello all. Just got my 71 N600 on the road. All ok for the first few test drives – but just today while driving found both front brakes becoming more and more stuck on. Rears were fine.Got home and let cool down.After an hour of cooling found both front wheels free to turn – and all ok at the wheel cylinders. Thinking since both front brakes stuck on it was not likely a case of jamming calipers or similar.Thinking something in the master cylinder or booster…? The master cylinder check valves have different part numbers for front and rear c ircuit.Does anyone know how to tell which is which? And why they are different ?The check valve seat is also a different part number for front and rear. My MC has a rubber seat with notches on sides for one circuit and steel washer for the other circuit…??? Would something sticking in the booster cause brake pressure to remain when the brake pedal is released? Thank You. Greg PrenticeToromont Power Systems905 488 2571
This e-mail and any attachment s may be confidential or legally privileged. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited. Please notify us immediately by email at corpmail@... or by telephone (collect if necessary). Please delete this email and destroy any copies. Thank you for your cooperation.
Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7 www.toromont.com (416)667-5511.
Ce courriel, ainsi que tous les fichiers joints, sont considérés comme confidentiels ou juridiquement privilégiés. Si vous n'êtes pas le destinataire désigné du présent message, soyez avisé que toute divulgation, copie, distribution ou action se fondant sur le contenu est strictement interdite. Veuillez nous en aviser immédiatement par courriel á l'adresse corpmail@... ou par téléphone (à frais virés si nécessaire). Veuillez effacer ce courriel et toute copie éventuelle. Merci pour votre coopération.
Toromont Industries Ltd., 3131 Highway 7 West, Concord, ON, L4K 1B7 www.toromont.com (416)667-5511.

Bill · Post by **Bill** » Tue Aug 07, 2018 9:41 am

Hi Greg; Make it happen.. Bill From: anzhonda600owners@yahoogroups.com [mailto: anzhonda600owners@yahoogroups.com ]
Sent: Tuesday, August 07, 2018 7:53 AM
To: anzhonda600owners@yahoogroups.com
Subject: RE: [anzhonda600owners] N600 master cylinder check valves Thanks all for your feedback on my brake issue… I disassembled the booster and found brake fluid where it should not have been. I am going to send the unit to Karps for rebuild. Thanks. From: anzhonda600owners@yahoogroups.com [mailto: anzhonda600owners@yahoogroups.com ]
Sent: Monday, August 06, 2018 11:45 PM
To: anzhonda600owners@yahoogroups.com
Subject: Re: [anzhonda600owners] N600 master cylinder check valves The way to tell where the blockage is ,loosen the front brake lines where the go into the booster. . I'm better it's the booster sticking Sent from my Verizon, Samsung Galaxy smartphone -------- Original message -------- From: " D & K Grandinett grandinett@... [anzhonda600owners]" < anzhonda600owners@yahoogroups.com > Date: 8/6/18 8:31 PM (GMT-05:00) To: anzhonda600owners@yahoogroups.com Subject: Re: [anzhonda600owners] N600 master cylinder check valves
We've also had the same binding brake experience. We diagnosed our problem by cracking the tube nut at the front brake outlet of the Master Cylinder to relieve the pressure in the primary circuit to the remote Booster. We actually had to perform that procedure just to make it home a couple of times, but it did confirm that the issue had to do with a blocked or stuck MC check valve. I'd try this pressure relief technique just to see if it temporarily resolves your issue.
I understand that these front and rear check valves are allegedly different, but frankly in my case they appear identical so I can't tell you how to identify one vs the other. Disassembling and carefully cleaning both check valves and a thorough purge bleed of the MC and front brake hydraulic circuit finally resolved our issue. Apparently the very small orifices in these check valves are very sensitive to any dirt or foreign material (including any material coming from old or deteriorating supply lines from the reservoir which also should be checked and replaced if necessary).
My suggestion would be to consider replacing the reservoir lines if they're showing any signs of being around just a bit too long, clean the MC, reservoir and check valves in "clean room" conditions and purge whatever's left with a fresh round of virgin brake fluid through the front system.
Your issue may not be the same because those remote boosters are notoriously sensitive as well, but this simple approach may be a place to start. Good luck.

On August 4, 2018 at 6:05 PM "Greg Prentice GPrentice@... [anzhonda600owners]" < anzhonda600owners@yahoogroups.com > wrote:

Hello all. Just got my 71 N600 on the road. All ok for the first few test drives – but just today while driving found both front brakes becoming more and more stuck on. Rears were fine. Got home and let cool down. After an hour of cooling found both front wheels free to turn – and all ok at the wheel cylinders. Thinking since both front brakes stuck on it was not likely a case of jamming calipers or similar. Thinking something in the master cylinder or booster…? The master cylinder check valves have different part numbers for front and rear c ircuit. Does anyone know how to tell which is which? And why they are different ? The check valve seat is also a different part number for front and rear. My MC has a rubber seat with notches on sides for one circuit and steel washer for the other circuit…??? Would something sticking in the booster cause brake pressure to remain when the brake pedal is released? Thank You. Greg Prentice Toromont Power Systems 905 488 2571
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