More issues with Baer calipers

[Van B]

I ran a track event at Road America yesterday and had an issue with the brake system. I have bled the system to death and still can't seem to get it to work right. The only way to get good pedal feel is to pump the pedal once or twice. When I try to bleed them, no more air comes out.

The system: Baer supplied cast master cylinder (manual) which is supposed to be 15/16 bore. I am not sure of the diameter of the stainless lines I had a local shop make. 6 piston front calipers and single piston pbr calipers on the rear.

I had a line loc on the car when I had the lines bent and at the time wanted to keep it. The fab guy had the idea to use the line loc solenoid as a tee between the front brakes. Could this be my issue? I have no brake fluid leakage and yes, I attached the pushrod to the recommended hole in the pedal.

Any ideas?

[Bow Tie 67]

Jeff,

It sounds like your getting pad knock. Where the rear brake pads get knocked back, which requires the 1st pump to take up the clearance.

Check out this link I found with a quick search.

http://www.trackpedia.com/wiki/Brakes

Are you running a 12 with c clips?


By the way, I'm jealous that you have already been at the track. I may hit a parking lot ax next Saturday.

Matt

[SHANE 73Z]

Jeff,

I have a similar issue going on right now, although our specifics are a little different. After any length of time without applying the brakes mine needs a pump to get the pedal back. My setup is SSBC calipers (D52 replacements) & 12" rotors in front, C4 12" rear & bias bar with wilwood .7" masters.

I am going to try a couple of 2lb residual valves in the lines. This should keep a little pressure in the lines so fluid cannot go back through to the masters. Wether the problem is pad knockback or just fluid seeping back through the system, I am hoping this will solve it.

Shane

[PTAddict]

With the single piston rear calipers, you shouldn't be getting pad knockback on the rear, at least if your caliper is floating freely. With a fixed position caliper and C-clips, you can get pad knockback big time - I had big problems with this on a previous car with 4-piston Wilwoods.

Pad knockback on the front is a real possibility, and is very difficult to solve. If your problem only occurs after a hard corner, then goes away until the next corner, it is almost certainly knockback. I know that some caliper manufacturers have "anti-knockback" springs available which go behind the pistons in the caliper - you might check with Baer on this.

[Van B]

I think I had a combination of things going on. I finally got a chance today to look a little closer. At the track I had a lot of brake dust on the rear of all things. Upon looking today, I found the rear pads almost completely gone. I had the proportioning valve at 4.5 turns from minimum per Baer's instructions. I have since backed it off completely, which the instructions state will give about 57% pressure to the rears. I plan to put new pads in the rear and start experimenting.

I still believe I had a knockback issue or something going on with the fronts, but I was surprised to find the rears as I did.

[tripower]

I think I had a combination of things going on. I finally got a chance today to look a little closer. At the track I had a lot of brake dust on the rear of all things. Upon looking today, I found the rear pads almost completely gone. I had the proportioning valve at 4.5 turns from minimum per Baer's instructions. I have since backed it off completely, which the instructions state will give about 57% pressure to the rears. I plan to put new pads in the rear and start experimenting.

I have the Track front/Touring rear set up from Baer and found similar - brake dust is heavy on the rears and the front rotors look virgin! (No dust on the front rims too). I have the adjustable Baer valve turned ALL the way out so it's supposed to be at 57% already!!!! Not sure what my deal is yet...

[Happyfunballs]

Are you guys able to lock up the brakes with you Baer systems? I can't seem to.

[Van B]

After I adjusted the prop valve all the way out, the rears lock up just after the fronts. I did notice the right and left did not lock at exactly the same time, but it looks like the right side has a little more pad transfer on the rotor.

[John Wilmesher]

I was getting ready to order Baer track/sport set up for my 70 Fbird, now not so sure. Plus, no one seems to have a 17" wheel that they guarantee will fit.

[Van B]

Wow, this is an old post. Don't let my problems hold you back. I did not bench bleed the master, which was the cause of my spongy pedal problem. They stop the car like hitting a brick wall. 6S calipers on front with 14" rotors.