81-87 rear brake circuit have residual check valve stock?
 

Do 81-87 rear brake line/ circuit have residual check valve stock or is it just a strait shot from the combo valve to rear brake hose?
Thanks
Clint

Re: 81-87 rear brake circuit have residual check valve stock?
 

All the one's I've worked on were a straight shot after the prop valve. My 89 dually as well.

Re: 81-87 rear brake circuit have residual check valve stock?
 

Thanks, I looked and didnt see anything other than what looked to be unions... but wanted to ask just in case

Re: 81-87 rear brake circuit have residual check valve stock?
 

Yep.... Unions are all I recall seeing as well.

Re: 81-87 rear brake circuit have residual check valve stock?
 

Wouldn't the Residual Pressure valve be located in the outlet of the Master Cylinder for the rear drum brakes?

Re: 81-87 rear brake circuit have residual check valve stock?
 

Isn't there a valve in the prop valve that can flip and not give pressure to the rear? Should light up the BRAKE light on the dash. I believe there is a tool to hold it in place while bleeding

Re: 81-87 rear brake circuit have residual check valve stock?
 

Cpp has a tool to keep the Brake light from tripping... pretty crappy quality, its threads are too small so it feels like it is cross treading.. will it work yeah, will it damage anything no, but I will probably mak a tool out of the old sensor that I probably wont ever use... I picked up cop disc / disc valve finally.. I'll install it in a few weekends.
Just replaced the rear drop brake line..
Sum b, had to replace the brake end fitting as it rounded off.
Clint

Re: 81-87 rear brake circuit have residual check valve stock?
 

Slightly off topic, but has anyone ever heard of anti-locking rear brakes on an 87? Any information on them? Just noticed it's on my window sticker.

Re: 81-87 rear brake circuit have residual check valve stock?
 

Rob, 88's had it standard, so it could have been an option in 87. I have never owned or driven an 87 so not sure. Newest square I have had was an 83.

Re: 81-87 rear brake circuit have residual check valve stock?
 

Interesting. I don't see any ABS modules, just thought it was interesting on this year model. Thanks Bill!

Re: 81-87 rear brake circuit have residual check valve stock?
 

I have an 87 3/4 ton. It came from the factory with a load-control valve above the rear axle. Supposedly under very heavy braking conditions, the rear of the truck would lift up, and would be prone to locking the rear brakes. This valve would close off the rear brake line, and reduce the chance of the rear locking up in these conditions. This valve is commonly removed.

I don't know if the 1/2 tons had the same valve. If so, GM may have called it anti-lock brakes, as a marketing gimmick.

Keith Seymore would know what's meant by "anti-lock brakes", I'm sure.