Hey, just wondering if we have these, and where it's at?
http://pavementsucks.com/forums/viewtopic.php?topic=84451
http://pavementsucks.com/forums/viewtopic.php?topic=84451
CK5
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Do we have Residual Valves? Where are they?
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I dont think so, I only say that because when I did my rear discs I did alot of searching to see what kind of results people where getting in regards to how the brakes were reacting. And I seen alot of proportioning valve changes/mods, master cylinder upgrades...etc. And I have never heard anyone talking about a residual valve that came on our trucks. Maybe in the later years but defnitely not my 87 blazer or 86 crew cab have one.If you want to buy one tsm has them. Just scroll down to the residual valves on the page.
http://tsmmfg.com/Brake_Accessories_others.htm#RESIDUAL%20VALVES
http://tsmmfg.com/Brake_Accessories_others.htm#RESIDUAL%20VALVES
There are two different uses for residual valves. The 10 lb valve is used to hold a residual pressure to the drum brakes to give a higher firmer pedal. The 2 lb valve is used in the disc when the master cylinder is lower than the calipers to prevent back siphoning of the fluid from the master.
Out trucks never came with residual valves.
Out trucks never came with residual valves.
sled_dog
1 ton status
umm thanks for quoting the first thing you found on Google?
Are we really certain our trucks never came with Residual valves? I've never gotten a conclusive answer.
Residual valves are onl used with discs when the master cylinder is mounted lower then the calipers(thus the back siphoning mentioned).
Are we really certain our trucks never came with Residual valves? I've never gotten a conclusive answer.
Residual valves are onl used with discs when the master cylinder is mounted lower then the calipers(thus the back siphoning mentioned).
You like that! Amazing, that google thing.
I took a scan of the 73-78 and 79-84 GM parts books, no residual valve is listed. For C,K,P,G vehicles. Mabey on '85 and up, but I highly doubt it. I scoured groups 4 & 5. Nothing. THere was a factory D-Shaft parking brake offered on P-Chassis though, a mini drum setup up. Sweet! Learn something new every day!
I took a scan of the 73-78 and 79-84 GM parts books, no residual valve is listed. For C,K,P,G vehicles. Mabey on '85 and up, but I highly doubt it. I scoured groups 4 & 5. Nothing. THere was a factory D-Shaft parking brake offered on P-Chassis though, a mini drum setup up. Sweet! Learn something new every day!
sled_dog
1 ton status
good to have a reference based answer to this question
used to prevent back feed of fluid when master is lower than calipers/wheel cylders.
73k5blazer said:
But did you disect a brake master cylinder?
Usually the OE's put the Residual Pressure Valves (RPV) in the master cylinder. They're in behind the seat for the brake tube in each outlet port. The way to remove that seat is to run a tap, usually a 6-32 works well, into the hole in the center of the tube seat. It will eventually bind against the RPV bits and if you keep going it will extract the seat. Sometimes you have to go to a long screw the get the seats out. Once the seat is out the RPV bits will fall out of the m/c. If you've done a carefull removal job you can then put the seat back in w/o the RPV bits in place.
I did. They had every part broken out in the master group. Nothing resembling a residual valve.
Not meaning to start something, I just searched and searched, I believe this was covered before, but I can't find it.
I'm almost certain my service manual (no access to that for awhile!) shows that at least a couple of the multiple master cylinders listed for the trucks have a valve that is pressed into the seat where the brake lines seat.
Take it with a grain of salt, like I said, I don't have my references to double check, and it's been a long time.
I'm almost certain my service manual (no access to that for awhile!) shows that at least a couple of the multiple master cylinders listed for the trucks have a valve that is pressed into the seat where the brake lines seat.
Take it with a grain of salt, like I said, I don't have my references to double check, and it's been a long time.
I didn't check the service manual. I'll check that when I get home. I was looking at the parts books. I could have missed it. Alot of thier names don't make a heck of a lot of sense. I was looking for 'valve', 'residual', 'pressure', or any name I didn't know what it was in the master parts section. Didnt' see anything. But I've been accused of being a bad looker before.
