i just swapped out my 10 bolt with drums for a 9 bolt with disc brakes, what proportioning valve should i go with? ive been looking at the adjustable ones but is there a stock one that would work? or is an adjustable one a better option?

 

Are you done with the swap? Do your brakes work now?

 

Yes. But we need more info about the year of your car and what type of brakes the 9-bolt has (iron Delco-Moraine or alum PBR's).

The following is about 10-bolts but the brake info (toward the bottom) is the same as for the 9:

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

JamesC

 

well what happened is this, i had a rebuilt 10 bolt with 3.73 gears and my brother had this rebuilt 9 bolt with 3.45. I went with a turbo so i wanted lower gears and he wanted my 3.73s so it worked out great for me. On his thirdgen which came factory with drums, the rear brakes werent good, its like they werent getting enough pressure. I belive everything is stock like new stock rotors, new calipers and new pads.

My car had great brakes with the drums and i wouldnt want disk brakes to be a "downgrade" lol

 

Use the correct combination valve as noted in the link above and you should be good to go. You might take note of the speedo drive and/or driven gears as well as the parking brake cables.

JamesC

 

so just to make sure, my car is a 89 trans am, if i get a 89 1LE proportioning valve i should be all good to go? and should i also get 1LE parking brake cables? or will the stock drum cables work? i didnt quite understand that part. THanks for all the help

 

Does the 9-bolt have alum (PBR) calipers? If you're unsure of what those are, check my vBgarage on the lower left for pics. If the above is what you have, you need the J65 (the RPO for 4-wheel disc brakes) 1LE combination valve, first design, along with first design rear disc parking brake cables.

If you have iron Delco-Moraine calipers, you'll need the mid-eighties J65 combination valve and mid-eighties rear disc parking brake cables.

I'm assuming you have the tunnel-mounted parking brake adjustment feature in you car.

JamesC

 

they dont seem like aluminum to me this is what they look like




are these the brake cables i would need for this application?? thanks for all your help JamesC
http://cgi.ebay.com/ebaymotors/88-89...item5ad344ff43

 

I used a Summit adjustable valve when I converted to disk's. I can now make the brakes feel the way I want. By the way, you may think that your car will stop the best with the pressure turned all the way up, but thats not the case. About midway is where the car stops the best. Heres a pic of where I put it. Its real easy to just reach under the car and adjust it. No need to jack the car up.

(pay no attention to the ugly exhaust. Its off the car and the new exhaust starts going on tomorrow.)

 

Those are the iron Delco-Moraine, 82-88. Since the advertisement is for 88-90, I suggest the cables are for the alum PBR's, 89-92.

JamesC

 

i like the idea of the adjustable proportioning valve but i would have to put it in the factory location and im sure the threads will be dif. than factory. I think it might be easier to get the 1le proportioning valve that will be a direct fitment

Since those are standard brakes, and not the so-called 1LE's (PBR's), I recommend the standard J65 valve, post #7.

JamesC

 

Goes, sorry, I inadvertently edited your post by inserting my reply.

 

haha i was wondering what happened to my post. lol Thanks for all your help that really helped me out alot.

 

rather than reposting a new post I have a similar question to the one posted. It's just hard with all the different brake lines, master cylinders, and prop valves combinations for every year. I tried reading through many posts and spent several hours trying to find my answers.

I have an 85 z28 that i swapped out my broken 10 bolt drum brakes for a 9 bolt disc brakes with i believe the PBR brakes. i just want a straight answer if anyone could be so kind to help about what needs to get replace from my stock M/C, prop valve to get my rear brakes working a little better than normal. or does the master cylinder even need to get replaced or is it just the prop valve.

 

Your master is fine. You'll need to change the combination valve to the first design 1LE, which you can purchase from the following site:

http://www.flynbye.com/catalog/i40.html

JamesC

 

alright thanks a lot should all the brake lines and from the M/C to prop valve to other brake lines match up properly with the part?

 

Yes, bolt up--was on my 85.

JamesC

 

hi guys, i hope youre all still around to help. im having the same issue. its an 85 z28 that originally had a 10 bolt with drums. a 9 bolt was swapped in before i bought it. i was told its from a T/A GTA but who knows for sure. The calipers are the iron delco ones. ebrake doesnt work and it doesnt stop super well.


so my questions are this.

what brake pads and rotors will fit
what e brake cables do i need to make it work
should i get the 1le valve from flynbye, will it help with the poor rear bias

heres a pic of the valve in there now. not sure if it was changed with the conversion

 

I'm sorry fellow thirdgener. Its been awhile since I've done my swap. I never got my ebrake working, but didn't put much effort forward. I believe I swapped the prop valve from another junk yard camaro/firebird that had a 9 bolt. The car never stopped after the swap as good as I thought it would, but it was better than it was before with the drums so i was fine with it. As far as the size i just swapped whatever autozone size recommended for a 9 bolt Camaro/firebird.

n8