6066 (1960-1966) GMC Truck Club

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-   -   hydraulic clutch residual pressure valve (https://6066gmcclub.com/showthread.php?t=50985)

bostru November 10th, 2020 11:57 PM

hydraulic clutch residual pressure valve
 
Where can I buy a residual pressure valve for 1960 GMC Pickup with hydraulic clutch. And does anyone know what the pressure value is in P.S.I

Funky61 November 11th, 2020 12:48 AM

Re: hydraulic clutch residual pressure valve
 
Welcome Bostru!

Is this valve on the hydraulic slave cylinder and would you mind posting a picture?
If it is, I know that some did not have that valve on there.
My 61 does not have one; it just has a bleeder screw.

bostru November 11th, 2020 01:02 AM

Re: hydraulic clutch residual pressure valve
 
Truck is in storage so I can't get pics but the valve is at the slave cylinder right where the line goes into the cylinder . It is about 3/4"long looks like a brass adapter. Not all trucks used these apparently but were used in brake systems on early cars and trucks where the master cylinder was located on the frame . idea was to hold slight residual pressure (approx. 10 PSI)
on the brakes . I assume this valve does the same with clutch

James November 11th, 2020 09:58 PM

Re: hydraulic clutch residual pressure valve
 
Quote:

Originally Posted by bostru (Post 73273)
Truck is in storage so I can't get pics but the valve is at the slave cylinder right where the line goes into the cylinder . It is about 3/4"long looks like a brass adapter. Not all trucks used these apparently but were used in brake systems on early cars and trucks where the master cylinder was located on the frame . idea was to hold slight residual pressure (approx. 10 PSI)
on the brakes . I assume this valve does the same with clutch

The purpose of the pressure is to make sure the wheel cylinders/slave cylinder seals from collapsing and allowing fluid to leak out. This is used on all vehicles with drum brakes/hydraulic clutch. With drum brakes it is located in the master cylinder. On the clutch I am not sure if it in the clutch master cylinder (I would think it would be here) or the slave cylinder.

bostru November 11th, 2020 11:49 PM

Re: hydraulic clutch residual pressure valve
 
The residual pressure check valve in a brake system is to keep slight pressure applied to the brakes at all times which will reduce pedal travel and make the brakes apply quicker . (probably splitting hairs as to how much quicker) .The valve in the hydraulic clutch system works in the same way . Do you know where I can get an OE valve for the clutch on a 60 GMC with a 305 ?

Thanks for your reply

James November 12th, 2020 12:48 AM

Re: hydraulic clutch residual pressure valve
 
Quote:

Originally Posted by bostru (Post 73279)
The residual pressure check valve in a brake system is to keep slight pressure applied to the brakes at all times which will reduce pedal travel and make the brakes apply quicker . (probably splitting hairs as to how much quicker) .The valve in the hydraulic clutch system works in the same way . Do you know where I can get an OE valve for the clutch on a 60 GMC with a 305 ?

Thanks for your reply

I know a lot of website is saying the same thing. However applying brake quicker was not the original issue, it is leaking wheel cylinders. Please refer to the expert at: https://www.freeasestudyguides.com/r...eck-valve.html
This is in a practice ASE test.

bostru November 12th, 2020 01:01 AM

Re: hydraulic clutch residual pressure valve
 
Thanks ,do you know where I can get one for my clutch and do you happen to know the value in PSI for the clutch valve

Funky61 November 12th, 2020 06:33 PM

Re: hydraulic clutch residual pressure valve
 
I would check with this company

https://www.wilwood.com/Search/PartN...ual%20pressure

I’m certain they could provide more specifics as well as the valve.

jagarra November 12th, 2020 07:49 PM

Re: hydraulic clutch residual pressure valve
 
These are available. https://www.speedwaymotors.com/Wilwo...gs,233816.html

bostru November 12th, 2020 09:44 PM

Re: hydraulic clutch residual pressure valve
 
Thanks, Funky61 and Jagarra I am aware of the aftermarket valves but am looking for an Original Equipment piece for another project N.O.S. or nice used .
Thanks again

James November 12th, 2020 11:39 PM

Re: hydraulic clutch residual pressure valve
 
The slave cylinder comes in two sizes, 1" or 1-1/6". Which size do you need so we know what to look for?

James November 12th, 2020 11:41 PM

Re: hydraulic clutch residual pressure valve
 
This one is 1-1/16":
https://www.summitracing.com/parts/dhb-cs36124

bostru November 12th, 2020 11:46 PM

Re: hydraulic clutch residual pressure valve
 
Thanks, but as posted in the first post I am looking for the residual pressure valve not the slave cylinder .

James November 12th, 2020 11:53 PM

Re: hydraulic clutch residual pressure valve
 
This place has both sizes, however it is listed for a 1961 instead of a 1960. The only different I see is the 1961 listing has a CS in the part number.
https://www.rockauto.com/en/catalog/...+cylinder,2044

James November 13th, 2020 12:13 AM

Re: hydraulic clutch residual pressure valve
 
Quote:

Originally Posted by bostru (Post 73287)
Thanks, but as posted in the first post I am looking for the residual pressure valve not the slave cylinder .

This day and age you might not be able to find an OEM residual pressure valve for the slave cylinder. This is why I suggest the slave cylinder. The only possibility is NOS parts on ebay, but you might have to wait for someone to list it.

Funky61 November 16th, 2020 01:29 AM

Re: hydraulic clutch residual pressure valve
 
2 Attachment(s)
Here is information from the early manuals I have and they call it a Hydraulic Fluid Damper.

bostru November 16th, 2020 03:44 PM

Re: hydraulic clutch residual pressure valve
 
Funky 61 ,I have located one . Thanks fo the pics, your 61 does not have one ?

Funky61 November 16th, 2020 05:07 PM

Re: hydraulic clutch residual pressure valve
 
That's great news Bostru!

Where did you source one and is it factory and do you know what PSI it is?

No my slave cylinder does not have one.

bostru November 16th, 2020 08:42 PM

Re: hydraulic clutch residual pressure valve
 
Junkyard find ,don't know anything about it . Not much info on these and the service manual doesn't tell much either .

James November 16th, 2020 10:32 PM

Re: hydraulic clutch residual pressure valve
 
I found one NOS GMC:
https://www.oldsobsolete.com/product...ve-gm-5460337/

Funky61 November 16th, 2020 10:44 PM

Re: hydraulic clutch residual pressure valve
 
Awesome Work James!

bostru November 16th, 2020 11:24 PM

Re: hydraulic clutch residual pressure valve
 
Second that ,bought a junkyard piece should work fine for what I am doing but good to know I have a second choice . Can't imagine much demand for this part . Thanks for your help !!

James November 17th, 2020 12:36 AM

Re: hydraulic clutch residual pressure valve
 
This is what teamwork is all about. There is not one person with all of the answer, but with everyone help we get there.

bostru November 17th, 2020 12:54 AM

Re: hydraulic clutch residual pressure valve
 
Yes indeed!!


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