Can you use a 87 prop valev for disc/disc on a 91 car that im swapping a 9 bolt into?

i believe the ac delco part number for the disc/disc valve is 172-2005 - am i right?

 

The combination valve is fine as long as the 9-bolt has iron Delco-Moraine calipers. The issue, however, is that the 87 valve won't fit your 91 as the tube nut threads are different.

JamesC

 

so what should i do?

 

Good question.

You could retain the drum valve (I assume that's what's currently in the car). While it would work, best braking performance wouldn't be achieved.

You might try to find a fitting and/or fittings that would accommodate your 91's M1.5 tube nut threads at one end and the 87's M1.0 tube nut threads at the valve. I have no idea if such a fitting exists or whether it would work.

You could cut the lines, slip on the correct fittings from an 84-88 and reflare the lines. How much grief that would cause, I'm uncertain.

Hopefully, some who has experienced your issue will chime in.

EDIT: You could swap to bigger brakes, such as the so-called 1LE's (PBR's and 11.7" rotors) and simply use the correct second design 1LE valve, which would bolt up to your 91.

http://www.flynbye.com/catalog/i172.html

JamesC

 

You could try an adjustable proportioning valve. Not sure what fittings work with which ones etc.

 

Thanks, I was on the verge of editing that suggestion in. Good call.

JamesC

 

hmm so far cutting the lines and slipping on the correct fittings from an 84-88 and reflaring the lines seems like my best bet, not sure where i would get those fittings though

 

what about using a tap n dye and opening up the valve

 

Hey, Pat,

Replying to your PM:

Using the tap/die method would be new territory for me. Frankly, I don't know whether it would work or not. I'd think the easiest method would be to throw in an adjustable.

Where part numbers for the disc/disc combination valve is concerned, the following is from my 82-91 Parts and Illustration Cat:

Valve, Comb (J65) (1986-88) 14089497

I suggest any 84-88 valve (as long as it's the alum type) would work. I'd hit the bone yards and see what's available.

JamesC

 

im gonna try it and buy the 14089497 valve and rethread it to fit, ill report back and let you guys know if it works

 

You will NOT be able to rethread the valve. The fitting size is too close and the threaded port has a tapered seat at the bottom and if you damage it you will never be able to get the lines to seal. Only thought I had would be to swap the guts of one valve into the other, I believe they are compatable internally. I would try this long before trying to retap the valve and if that all fails, go with an adjustable vave.

 

what adjustable valve do i get? and how hard is it to adjust it? that kinda sounds like a pain in the butt, plus if it is adjustable with a **** couldnt it easily come out of adjustment over time, just by road vibration or whatever?

Can I use the late 1LE valve wth the iron calipers? But from what im told that vale is near impossible to get...

 

Actaullay I think I found a 10164112. think thats exactly what i need.... Gmpartsdirect.com showed it then i clicked on it and went to check out and they wanted 416 bucks for teh shipping... what a scam.. but i found it somewhere else