Front Brakes - New pads won't go in ('84 911)

[TheGreg]

Newbie doing his first brake pad job here.

It has gone ok so far, I got the left fronts replaced and I moved over to the right. Old pads out...no prob. But the new outboard pad won't go in, calipers are retracted fully as far as I can tell. I even released pressure on the brake lines to help with pushing the calipers in.

Inspecting the old pads, it appears that they wore unevenly and the gap between each side is different. The inboard pad goes in smoothly.

Kinda stuck...what am I missing...gonna have to put old pads back for now.

[midnight911]

are you saying the pad is not going into the caliper with the piston getting in its way? trying to understand what the problem is...

if this is the case, put the old pad in and use the pad to lever the piston retract more.

[mreid]

Sounds like you may have a seized piston. How old is the caliper?

[TheGreg]

so...

The Caliper is not frozen, it does retract, just not enough to allow the gap to be wide enough for the new wider pad to slide in...

I switched the old pads (inboard to outboard) hoping this would "even it out" somewhat. It may have helped some, but still the gap does not become wide enough on the outboard side.

[TheGreg]

Got it. With the old pad IN i _carefully_ used a screwdriver to force the caliper back. Voila! It seemed to all of a sudden want to push back. I can now get my new pads in. Is this an indication of necessary maintenance needed on my caliper?

And as to how old is the caliper...I'm a new owner, I'll review the records. But old is too old.

[midnight911]

the need for retracting pistons when putting thicker pads is normal. you should be fine but rebuilding calipers is not a bad idea if neglected for a long time.

how much is the wear difference?

[vince_aust]

sounds like you resolved your problem - just remember forcing calipers back in also causes brake fluid reservoir levels to rise - check so you do not get a brake fluid spill. I usually use a plastic syringe to remove fluid. If you are draining system then ignore my comment

[Jdub]

The caliper puck is reluctant to budge because you are asking it in a single stroke inwards to overcome thousands of incremental inching out over time. Plus the newly-exposed puck surface has minor corrosion you must also overcome by force.

I would recommend a manual bleed of the system after putting new pads in. It's just a habit with me unless the system's fluid is quite new.

[TheGreg]

Yeah, I was planning in bleeding the lines during the job. Had a different wrinkle with that, I couldn't get the motive pressure bleeder cap to seat onto the brake fluid reservoir. No worries, just did a manual bleed. Looks and feels good, test drive around the block was good too.

I think I'm all done.