Shops in NW Indiana/Chicago area

[Toadman]

Having a hell of a time with my disc brakes. Anyone know of a shop in the Dyer, Indiana area that can troubleshoot them? I would prefer a shop familiar with race car brakes. Everyone locally that I mention "adjustable proportioning valve" to gets a glazed over look in their eyes.

[andrewb70]

What seems to be the problem? List the components in your braking system. What kind of car?

Andrew

[Toadman]

'77 Camaro, '81 Trans Am rear disc brakes (master cylinder, combination valve, and calipers), SSBC Force 10 front calipers, SSBC adjustable proportioning valve.

Everything worked great (didn't have the adjustable proportioning valve yet) for several years until I had a shop do an LS1 swap into my car this past winter. (He did an EXCELLANT job on the swap.) Since the entire front end of the car was off, and the brake lines easily accessible, I had him install the adjustable prop valve. I should've known better since he had no idea what that was. First he installed it dialing OUT the front brakes. YIKES! Then he installed it on the rear brakes with no combination valve and a tee to the front brake lines. The pedal sank all the way to the floor. Now I personally have re-plumbed the combination valve back in with the adj. prop valve on the output to the rear brake lines. Still no pedal pressure...

I have bled the brakes to death, and it has been suggested that I have them "power bled"... whatever that means. When I bled the brakes, I got fluid to squirt from the bleeders, so there must be some pressure. The shop that did the swap had the master cylinder off of the car for several months. Could it be some issue with that???

I obviously don't know enough about braking systems, and I'm likely in over my head. My newly stripped and painted subframe & inner wheel well have now been doused with brake fluid and the paint has peeled. I missed the Motor State Challenge because of this, and the Heidt's Performance Car Challenge is QUICKLY approaching! Not to mention, summer is finally here & I am dying to enjoy my car and my newly installed LS1!! I don't trust the guy that originally installed the prop valve to touch the car again, and like I mentioned, everyone I talk to locally goes, "an adjustable what...". I'll trailer the car to someone as long as I can trust them and know that I can pick the car up 100% ready to go.

[andrewb70]

.....

Everything worked great (didn't have the adjustable proportioning valve yet) for several years until I had a shop do an LS1 swap into my car this past winter. (He did an EXCELLANT job on the swap.)........

OK. Let's take this one step at a time. Brake systems are not rocket surgery and there is no reason that we can't figure out what's going on. In the statement above you said that everything was working great. So what happened that it stopped working?

Does your "combination valve" also reduce the pressure to the rear brakes?

Andrew

[Denvervet]

To start off I would bench bleed the master cylinder since it was off the car for months...probably ran dry. Then go from there.

[Toadman]

Not rocket surgery, but it is brain science!

Unfortunately, I'm not the one who reassembled the system, so I don't have all of the answers. As far as I know, the only things that changed were the master cylinder being put back on and the addition of the adjustable prop valve. Probably a no-brainer for others, but where exactly should an adjustable prop valve go in the system? You still use the original combination/prop valve along with the adjustable one, right?



Today I had a shop bleed the system. They said that they got some air, but the feel of the pedal didn't change. The brakes barely hold the car when it's in gear.

[andrewb70]

Not rocket surgery, but it is brain science!

Unfortunately, I'm not the one who reassembled the system, so I don't have all of the answers. As far as I know, the only things that changed were the master cylinder being put back on and the addition of the adjustable prop valve. Probably a no-brainer for others, but where exactly should an adjustable prop valve go in the system? You still use the original combination/prop valve along with the adjustable one, right?

Today I had a shop bleed the system. They said that they got some air, but the feel of the pedal didn't change. The brakes barely hold the car when it's in gear.

An adjustable prop valve goes in the rear line, BUT you need to make sure that the combination valve doesn't have some sort of pressure limiting function as well. If it does, and you add a prop valve, that will reduce your pressure to the rear brake tremendously.

I would take the adjustable prop valve out and go with the original set-up, which you said worked well.

Andrew

[Apogee]

If you adjust the adjustable proportioning valve all the way in (counter-clockwise), then it should allow full line pressure, the same as removing the unit entirely but a lot simpler. As Andrew stated, two prop valves in any given circuit is a recipe for bad brakes. Do you know whether you were running an OE GM style disc/disc or disc/drum combination valve before?

Also, bench bleed the master cylinder as stated previously. If you're not sure whether it needs to be bleed, disconnect the hard lines that attach to the master cylinder and plug both outlet ports, then apply the brakes. The master cylinder should hydraulically lock after about 1/8" of piston travel, so .125*pedal ratio for your pedal travel, approximately 1/2" for a second-gen F-body.

Tobin
KORE3

[Toadman]

I'm planning to remove the stock combination valve again, go back to a tee to the front brakes, and only run the adjustable prop valve on the rear. BTW the original combination valve was disc/disc. Probably wouldn't hurt to bench bleed the master cylinder too.

Shouldn't I be getting plenty of front brake pressure regardless of what the rear brakes are doing?

[Toadman]

Tobin, I checked out the KORE3 wesite. That stuff is bada$$! Gonna have to add a couple of kits to my future "to do" list!

[Bmf5150]

Where u have your ls1 swap done at?what shop???I'm in crownpoint and just recently finished my ls swap in my 68 Camaro!u can check it out here!!!



http://m.ls1tech.com/forums/showthread.php?t=1369420