87camaroz28.

hello, I have finally finished installing my Borg-Warner 9bolt posi disc rear end. well after all was done I started bleeding my brakes, and when I finished I noticed something wasn't right with my pedal, it goes almost to the floor, (I understand its a 87 Camaro, but I don't recall it being that bad last summer) also I was watching the rear when it was in the air, I put it in drive and hit the brakes, it slows down, and then will slowly start turning again.


I seen somewhere that I might have to get a different master cylinder, I guess theres one for (front disc, rear drum) and one for (disc front, disc rear)? anyone know if that is true, idk what it could be no air is in the lines I bleed them all the way around the car, front and rear. I have a few other ideas but wont ramble on just yet.


anyone eles have this issue?? any help? thanks this is the last thing I have to do till all is done and ill be

TTOP350

iTrader: (8)

You bleed the rear 1st?

JamesC

iTrader: (5)

Not true.

https://www.thirdgen.org/forums/susp...fferences.html

The combination valve is another story.

JamesC

87camaroz28.

should I replace the combination valve. I was talking to a guy at my family shop and he said it could be the master cylinder since they offer two different ones for drum or disc. he said it could change the amount of brake fluid in the rear. I sent for one to be ordered through oriley. but haven't gotten it, figured if anything I can always take it back.
any reason why it could be the combination valve?


and yes I did bleed the rear first, tested it out and it di the whole stop and slowly moving again. I drove the car yesterday after work, feels the same as it use to before I swapped rears, the pedal might be a bit lower cant remember, but I know it must of been like it before, never really tested the rear until now. so its got to be something up front.


did test out the posi though, haha

87camaroz28.

so if that post simply saying all it does is change the distance from the floor of the pedal? not sure if im reading that right. ill check in on this thread later, heading to the part store at 6-7ish after work,
debating on testing the difference of the master cylinders to see myself, if anything I can always take it back, it has a core but I have a part car (took it off that one just incase I want to take it back and cant get my old one)

JamesC

iTrader: (5)

For best braking performance, I'd say yes. There are three GM combination valves:
disc/drum
disc/disc (Delco-Moraine rears)
disc/disc (PBR rears)

More info below (there's no difference between 9- and 10-bolt braking systems):

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

87camaroz28.

Is pbr valve borg warner? Like for the 9 bolts,
What actually is pedal ratio

naf

iTrader: (7)

The cast iron delco moraines came with a different mc which supplies more fluid to the rear discs. Use of the disc/drum mc should not cause your pedal issue though. You may have let your mc get air in it while bleeding which can only be fixed by bench bleeding.

Best braking performance for the cast iron rears requires proper mc, prop valve, installation of the caliper recall kit and daily use of the parking brake to keep them adjusted.

If you have the aluminum pbr's you're much better off.

JamesC

iTrader: (5)

GM says the master doesn't matter. Note its recommendation in the link in my first post. It's all about pedal feel.

JamesC

naf

iTrader: (7)

More fluid flow with same pedal travel should result in firmer pedal feel. Same amount of work, less distance = more force.

JamesC

iTrader: (5)

I was always amused that the 1LE system called for the drum master.

JamesC