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Sat Nov 14, 2009 1:42 pm

I would do these checks first

Look first for leaking fluid on the right caliper. If none then take it out for a drive and see if it pulls to the right. If it does then the problem is on the left.

You may be feeling the piston move on the right one whereas the left one may be binding a little and not fully releasing when the brakes are released.

Sat Nov 14, 2009 1:59 pm

Right caliper is dry with no leaks on both ends of the metal line and around the pistons. Both pistons move freely. The pads are free from binding. The brakes are even - no pulling right or left. Tomorrow I'll take a look at the left caliper to see if the pistons are seized or not.

Sat Nov 14, 2009 2:20 pm

sounds good. You may find that one pad is a little more worn than the others - noticeably worn more. If so, that will be the side that isn't releasing. It can also be where the caliper isn't floating properly on the caliper bolts/pins so only one side of the rotor is completely releasing.

Sat Nov 14, 2009 2:44 pm

SGKent wrote: sounds good. You may find that one pad is a little more worn than the others - noticeably worn more. If so, that will be the side that isn't releasing. It can also be where the caliper isn't floating properly on the caliper bolts/pins so only one side of the rotor is completely releasing.

There's no caliper bolts/pins on a bus caliper and the caliper doesn't 'float'.

Sat Nov 14, 2009 3:25 pm

Quote: There's no caliper bolts/pins on a bus caliper and the caliper doesn't 'float'.

56OvalBug - yes that is correct. We just can't sneak anything past you.

however we answered it that way because not everyone here has stock brakes and we believe that sometimes people take what they learn here to other cars they own. The VW style system is not a common one even when they were being built but they are very well designed.

If you have time check the pad backing plates to be sure the PO or their mechanic put them back in the correct way.

I'd be interested in knowing what do you think of this brake job - complete rebuild w/ before and after shots. We had to hit them so hard the other day about 35mph that the fronts locked. I said to Cathy - at least we know they work without pulling....

BEFORE

AFTER

Sat Nov 14, 2009 3:29 pm

56ovalbug wrote: The air bubbles are gone - I think it may have been the switches not being tight enough. Guess I was a little paranoid of over tightening them when I first put the new master cylinder on. I tightened them both up along with one of the connections on the pressure regulator.

There's a problem with the right front caliper. If I put a line clamp on the rubber hose that goes to that caliper the pedal is firm and high. Take it off and the pedal goes down further and isn't quite as firm. I'll have to dig out one of my spare calipers and see if that solves the problem.

Would that not mean that the left is seized or the right has air in it.

Sat Nov 14, 2009 3:34 pm

Quote: Would that not mean that the left is seized or the right has air in it.
_________________
Brett

it could.

Sat Nov 14, 2009 6:14 pm

SGKent, nice job on the brake rebuild. Unfortunately that would only last about month in the weather conditions my '79 pane gets subjected to, then it would look worse than the before pic. I've owned this bus for nine years and I've done all the work on it myself. The backing plates are on correctly, arrows pointing up. I think the left caliper has air in it that just won't come out for some reason.

Sat Nov 14, 2009 6:28 pm

try this.

The right line is longer so do it first. Hook your hoses up - use a clear one and a bottle to catch the fluid and make sure the MC res is full.

Have your helper sit at the brake. Have them put a little pressure on the pedal and you open the bleeder then close it before they lift.

Have them pump firmly but not too hard 3 times. Pump Pump Pump and hold down on the third pump. You open the bleeder and let the pedal down firmly. That often dislodges air. Do this three or four times making sure you tighten the bleeder before they lift.

Check the MC and do the other side. See is that doesn't help.

If it doesn't, try the rears the same way as there may be air in the proportioning valve as well.

Sun Nov 15, 2009 12:01 pm

"There's a problem with the right front caliper. If I put a line clamp on the rubber hose that goes to that caliper the pedal is firm and high. Take it off and the pedal goes down further and isn't quite as firm. I'll have to dig out one of my spare calipers and see if that solves the problem."

It still has air in it. Try bleeding it again.

As I pointed out before sometimes you have to let them sit overnight then bleed again to get the last of the air out.

Mon Nov 23, 2009 7:01 pm

SGKent was correct :shock: :P. It ended up being a defective new master cylinder. The front port wasn't building pressure. I swapped it out with an old one I had lying around the garage and the brakes work fine. Hopefully CIP1 will give me a new one or a refund. I replaced the right caliper (after replacing the master cylinder) as well and it also made a difference in pedal firmness. The bottom bleeder on the old one seemed to be partially plugged as less fluid came out during the bleeding process.

Mon Nov 23, 2009 7:29 pm

56ovalbug wrote: The bottom bleeder on the old one seemed to be partially plugged as less fluid came out during the bleeding process. There are no bottom bleeders. The bottom valve is a drain to drain the fluid out of it. You don't and can't bleed it from the bottom. The top valve only is the bleed valve. Air rises, right? Air is at the top. That's why the bleeder is at the top. That might have been the cause of your problems all along. You should be refering to your service manual.

Tue Nov 24, 2009 3:54 am

Desertbusman wrote: 56ovalbug wrote: The bottom bleeder on the old one seemed to be partially plugged as less fluid came out during the bleeding process. There are no bottom bleeders. The bottom valve is a drain to drain the fluid out of it. You don't and can't bleed it from the bottom. The top valve only is the bleed valve. Air rises, right? Air is at the top. That's why the bleeder is at the top. That might have been the cause of your problems all along. You should be refering to your service manual.

That's what I thought too. But when I first put the new caliper on I only bled the top bleeder and the pedal was still a bit mushy. So, I tried the bottom bleeder for the hell of it and there was air trapped in there - I watched it come out in the clear hose I was using. Too bad the bottom bleeder is busted off the left caliper as I would bleed that one for the hell of it as well.

Desertbusman wrote: That might have been the cause of your problems all along. You should be refering to your service manual.

Nuh-uh... I replaced the caliper AFTER I swapped out the faulty new master cylinder.