After searching I have found that GM switched the proportioning valve halfway through the 89 production year. I have a 1989 IROC that came stock with 4 wheel disc brakes. I want to know if I have the right proportioning valve for 1le brakes. All I could find searching was 5 different GM part numbers for the 89 year, will the numbers on the side of the proportioning valve tell me anything?

 

You don't need part #s. Keep it simple.

Do you have the PBR aluminum rear calipers? If you do, then your PV is the same as the one they used in the 1LE cars. If you have the cast-iron calipers, then it's a different one.

 

I have the PBR rear calipers so i guess i have the 1LE proportioning valve

 

NO and NO.
even with the PBR rears, the prop valve on the 89 should be changed to the correct one....if you do the 1LE fronts.

I'm still running the factory prop valve, even after my 1LE front swap, and my brakes suck. I have the correct prop valve awaiting...

 

Okay now I am even more confused...

So what’s the part number of the proportioning valve you need for 1LE? 10136840?

 

Hey Luke. Since you have an '89, the numbers you need are 18014286 for the Master cylinder and the prop valve you need is either P/N 14089496 or 10136840, as noted below. (The M/C should not be an issue but I mentioned it anyway).

I had to use the 14089496 since my car is an '88. The info below is from Daniel Burke's 1LE upgrade page. More info to upgrade to 1LEs is in AndyZ28's 1LE CD rom. Excellent tool for the complete front and rear upgrade.

From Daniel Burke's page:

http://ws6transam.org/1LEbrake.html

"1LE Combo Valve (proportioning valve)

14089496 1989 1st design: M1.0 tube nut threads (For 1982 - early 1989 applications)
10136840 1989 2nd design:_ M1.5 tube nut threads (Late 1989)
10136840 1990-'92: M1.5 tube nut threads.

Measure your existing brake line tube nut threads before ordering. The Master cylinder tubes have one that is_ M1.5 and one that is M1.0_ so don't worry about them. Worry about your existing brake lines to the calipers and rear axle. "

You'll probably just have to measure them to be sure.

HTH...Ed

PS: I'd give Dal a call for the prop valve...his prices w/ shipping are great!

 

do you mean 10mm by "M1.0 tube nut threads" and 15mm by "M1.5 tube nut threads"?

 

Honestly, I don't know exactly....sorry. I assume them to be a metric thread pitch count, kinda like 1/4"-20 is a 20 threads per inch count on a 1/4" bolt, but there also is a 1/4"-28 thread also. I know they aren't 10mm or 15mm tube nuts. I think it's a 14 or 12mm wrench that I used.


Anyone else? Andy?


Ed

 

Anyone?? I am sure someone has had to deal with this before.

 

my rear brakes didnt even work. in the winter, when i try to stop on ice or snow, my rear tires keep pushing, and my front ones are locked up and slideing. so i got a tip from a different board www.gtasourcepage.com that said to remove the PV valve completely and sure enough my rear brakes started kicking in. the distribution feels perfect, and my rears never lock before my fronts. i also have an 89 (its a Trans am GTA though) and my brakes were brand new, so i figured something must be up. if you think your haveing the same problem, give it a shot. only thing is, you will have to find some way to plug the hole in the cap that houses the PV, i just drilled a screw into mine.

 

Did you mean to post this as a new topic? I am trying to figure what proportioning valve I need to upgrade to 1LE front brakes.



Does anyone know how to measure my threads and see if they are M1.0 tube nut threads or M1.5 tube nut threads?

 

i figured the reason why you were going to change them is because your rear brakes are crap. this will fix them.

 

89 Iroc Z, I hate to jump into your thread here...but I am confused also. I have an '87 Trans Am that was originally front disc rear drum and I have a SSBC 1LE setup for the front and '94 Z disc rear for the back. To understand this right...I need:

14089496 1989 1st design: M1.0 tube nut threads (For 1982 - early 1989 applications)

I just want to make sure this is right.

 

Thats right, you need the 14089496 vavle.



Can anyone help me on the thread sizes?

 

Thankk you 89 Iroc Z