new brakes, now no brakes Options

[anderssj]

(IMG:style_emoticons/default/sad.gif) end of a long and frustrating day. . .

spent the afternoon installing new rear calipers from PMB, new rear rotors, and new pads. followed eric's instructions (classic thread) on adjusting the venting clearance (I set it at .004"). Parking brake engagement feels normal. I've pressure bled the system twice now, still little/no pedal.  it feels like there's still air in the system, but I'm not seeing any bubbles the last two times I bled the system. no leaks at the lines, calipers, or bleeder screws either.

the only place I opened the lines was at the rear calipers; I capped them right away to prevent any big loss of fluid. When I finished reconnecting the lines to the new calipers, the brake reservoir was still about 1/2 full.

FWIW, I've rebuilt the rear calipers on this car in the past and have never had this problem before. I'm at a loss as to what to do next (aside from having a beer or two tonight). I'll probably try re-bleeding the system again tomorrow, but would appreciate any ideas in case I'm leaving something out.


Thanks in advance!

Steve A-

[dangerranger01]

I've experience (on other cars) with new calipers is it seems like air bubbles will stick on the inside and not bleed out. You'll have to tap on the calipers a few times and bleed again. Sometimes having to tap on the calipers again to help dislodge the air bubbles.

[anderssj]

I've experience (on other cars) with new calipers is it seems like air bubbles will stick on the inside and not bleed out. You'll have to tap on the calipers a few times and bleed again. Sometimes having to tap on the calipers again to help dislodge the air bubbles.

Thanks, I'll give that a try--have to be careful as those new PMB calipers are pretty!

[rangrbob]

I've experience (on other cars) with new calipers is it seems like air bubbles will stick on the inside and not bleed out. You'll have to tap on the calipers a few times and bleed again. Sometimes having to tap on the calipers again to help dislodge the air bubbles.

Thanks, I'll give that a try--have to be careful as those new PMB calipers are pretty!

I'm having the same issue with mine. At first, I did have the calipers on the wrong sides, so the bleeder valves were on the bottom and not the top. Fixed that, but they are still soft. I'll try it too.

[anderssj]

Yeah, thought about that, but mine is an early car with only one bleeder per side . . . and they're on the top of the caliper (but will double check). Thanks!

[anderssj]

OK, so I spent a few hours rechecking the venting clearance (three were at .004 and one was .006--all are .004 now) and re-bleeding the system (twice). Oh, made sure the bleeders were on top too.

While bleeding the system, I tapped along the lines from the pressure valve on the firewall all the way to the calipers--tapped on the calipers too. I got a few small bubbles out of the system,

Took it out for a drive after today's work and the pedal is still soft. (IMG:style_emoticons/default/mad.gif) The brakes are a little better than last night (not quite so "whoa-effin'-Nelly"), but it's still not nearly as good as it was before I started--worn pads, rotors, and all. Pumping it a couple of times when stopping seems to give me more pedal/better braking. I'm thinking that means there's still air in the system (pumping the brakes wouldn't effect any problems associated with venting clearance would it?).

I guess another check would be to see if the MC is leaking and causing the soft pedal. Hope not, as it's a relatively recent ATE 19mm unit . . . .

Updates to follow. Again, any advice/suggestions are appreciated!

Thanks in advance!

Steve A-

[MJHanna]

I would bleed the front brakes and check the pedal.

[GeorgeRud]

I couldn't get a really firm pedal after installing the newly rebuilt calipers until I took the car out for a ride on a bumpy road (carefully as the brakes were marginal), then re led the brakes with a pressure bleeder. I was surprised at how much more air came out after the good shaking! Now the pedal is great, but you have to be persistent in the bleeding.

[914Mels]

If you have a helper, jack up the car and pushing on the brake pedal, see if you can lock up either the front or back, or if you can lock up any disc at all. Also are you getting a strong stream of brake fluid out when you crack the bleeders or does it just dribble out?

[anderssj]

Thanks all,

I'm getting a nice strong stream of brake fluid out of all four calipers. I've been bleeding all four of the calipers starting with the furthest from the MC (RR, LR, RF, LF).

That's a good tip on driving then re-bleeding--I think I've done that in the distant past too.

I checked the pedal box before I put the car away for the day--nice and dry, so at least that's good.

This would all be so much easier if I didn't feel like hammered dog$hit. Fighting off my worst cold in memory. First-graders are walking petri dishes--irony is that it's my first cold from those kids, and I caught it on the last day of school. Go figure . . . .
(IMG:style_emoticons/default/dry.gif)