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Canadian Poncho Homepage -> Canadian Poncho -> Canadian Pontiac/Acadian/Beaumont Cars/Parts Wanted -> 69/70 B Body disc brake hold off valve. (Info).
Post Info TOPIC: 69/70 B Body disc brake hold off valve. (Info).
cdnpont


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69/70 B Body disc brake hold off valve. (Info).
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Anyone have a good 69 or 70 B body disc brake hold off valve? I have 2 69 types, but I think they are both seized in the open position.

Built my 65's 70 single piston caliper disc brake conversion without it, fronts work great, almost too good. Somewhat grabby. Going to need more rear braking at lower pedal pressures.

Thanks, Mark



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65 Laurentian post, 67 Grande Parisienne 4 door HT. 
 
seventy2plus2


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69/70 B Body disc brake hold off valve wanted.
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There's a guy who sells the kits to rebuild them, something like $12 US per kit. I can post a link later.

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70 2+2 convertible
70 2+2 hardtop
70 Parisienne hardtop
72 GMC Sierra

 

 
cdnpont


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Thanks Clint, but I can't see for the life of me how the 69 valve opens up. The 70 I understand, as it has a large nut that comes out.



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65 Laurentian post, 67 Grande Parisienne 4 door HT. 
 
oshawacliff


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Did I include the brake pressure set of 2 gauges From my tool box. Would that help to diagnose?

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Cliff

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Like the larger type for my eyes. 

 

 
cdnpont


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Thanks Cliff. True, I'd thought of the gauges, but it's not to that point that I'd need to measure it.

Just feels like it's all front at the lower pedal pressures. She'll stop fine, nice and straight, but you do feel the front start to dive somewhat.



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65 Laurentian post, 67 Grande Parisienne 4 door HT. 
 
4SPEED427


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I'm wondering if 68SD396RAG (John) has seen this. He's done likely hundreds of disc brake setups for guys and last I knew he still had lots of parts around. If he doesn't reply by tomorrow I'll give him a call.

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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles 

1966 Grande Parisienne, 396 1 of 23 factory air cars
seventy2plus2


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cdnpont wrote:

Thanks Clint, but I can't see for the life of me how the 69 valve opens up. The 70 I understand, as it has a large nut that comes out.

The 69 has the large nut, the 70 has a retainer ring.  

Pop off the rubber bumper, that will expose the center pin of the valve.  Then use a nut to straddle the center pin, and use a c-clamp to compress the part that the center pin comes out of, and you'll see the retainer ring.

email sent to you with the instruction sheets.



-- Edited by seventy2plus2 on Thursday 12th of November 2020 09:14:53 PM

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70 2+2 convertible
70 2+2 hardtop
70 Parisienne hardtop
72 GMC Sierra

 

 
cdnpont


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Thanks Clint.

Clint put me onto these excellent how to articles for the hold off valve. Great site! https://www.musclecarresearch.com/

Turns out I have a 1970 Valve,

 

Hopefully if the bore isn't too bad, I can rebuild it.

https://www.musclecarresearch.com/gm-1233464-autopsy

https://www.musclecarresearch.com/gm-1233464-rebuild

 

 



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65 Laurentian post, 67 Grande Parisienne 4 door HT. 
 
cdnpont


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RE: 69/70 B Body disc brake hold off valve. (Info).
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Got mine apart. The bore does not look good at all. Will likely need a new one at this point.

An example of how brake fluid absorbs water. Turns into sludge and rust.

grunge.jpg

 



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65 Laurentian post, 67 Grande Parisienne 4 door HT. 
 
oshawacliff


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A good reason for changing brake fluid every couple of years.

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Cliff

Done Hurryin

Like the larger type for my eyes. 

 

 
68sd396rag


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I have lots of rebuilt ones-let me know what date code etc.. you need John


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cdnpont


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Thanks John.

No particular date code required. Its for a  1970 single piston caliper disc conversion on the 65.



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65 Laurentian post, 67 Grande Parisienne 4 door HT. 
 
68sd396rag


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I will check tomorrow-pretty sure I have about 25 or so already rebuilt


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