V8Rumble

iTrader: (9)

Hey guys, I'm trying to replace the brake pads on my DD, I've gotten everything apart, I'm at the point where I need to reassemble everything - but the freakin' brake piston absolutely won't compress!!

I've tried using the normal tool that I always use (looks kind of like a metal brake pad with a bolt threaded through the center of it), I've tried using a BIG pair of channel-locks that I have, as well as my neighbor's welding pliers. I've applied enough pressure (using the pair of channel-locks) that it broke the handle on the brake spreader tool that I normally use. I've had my neighbor over here to lend a hand (he's a fireman who has forearms like Lee Haney) & he wasn't able to get it to budge either...

And yes, I do have the cap loosened on the master cylinder, but it's like there's a check valve or something that's holding the pressure in the line. I've tried releasing the bleeder valve, but that doesn't seem to help much... I've even called the service dept. at the dealership that's done a bit of the major work that's been needed, but all they told me was stuff that I already know.

Can anyone here offer any tips/suggestions?? It's starting to cloud up again, & I'm really hoping to get this done before the rain starts...

Thanks guys.

V8Rumble

iTrader: (9)

And when I say "won't compress", I mean "WON'T compress"!

I decided to (carefully!) see if I could "step up my game" just a little so that I could get it compressed just enough to slip the caliper over the new pads. So, I grabbed an 8" c-clamp from the drawer & found a 3-foot bar that I've occasionally used as a "cheater bar". The first couple of revolutions went OK - I was going slowly, paying close attention to how it felt...

The last 180* produced this:


(As you can see, I didn't beat the rain...) That's where I've left it for right now - trying to swap these brake pads (on just ONE wheel!) has cost me two tools, & caused a bit of pain in the wrist that I had repaired earlier this year - not worth chancing another problem with that! I'm a bit disgusted at the moment. I guess the good thing is that I didn't hurt the car, & I don't think that I did any lasting damage to myself...

Just gotta figure out HOW in the hell to get that last 1/4" or so...

JOHNNY59

iTrader: (398)

sounds like rust or corrosion on the pistons or bores. I would remove the pistons with compressed air and clean everything up and reassemble.

94FBIRD

iTrader: (5)

What car?

V8Rumble

iTrader: (9)

Errrrr... (No one was supposed to ask that!)

It's a (reasonably) late-model Saab 9-3... But it has a LOT of GM parts, both under-the-hood, & in the rear suspension, where I'm working now...

V8Rumble

iTrader: (9)

Wellll... I would hope that's unlikely. Things don't rust here that quickly, & the car still has less than 35k on it. I'll definitely take a look at the pistons tomorrow though, since mechanically, that could account for the problem...

I've pretty much decided that tomorrow morning I'm going to just disconnect the hose from the caliper block, clamp the hose(s) shut, fit the caliper over the rotor & new pads tomorrow, & deal with bleeding the brakes. It's been down for long enough already.

1BAD02WS6

iTrader: (-1)

Are you sure it's not a twist in piston? I don't get a lot of saabs at my work. A picture might help

01ssreda4

iTrader: (96)

So its compressed all but the last 1/4 inch? Anytime Ive ever had an issue with this a 1/4 turn got things going again.

V8Rumble

iTrader: (9)

Huh. To be honest, before reading these two replies, I'd never even thought about twisting the piston at all - and I've been doing brake jobs for over 20 years (although virtually every one of those has been on a domestic car...) That's just simple/dumb enough to work!!

Well, like I mentioned above, no, but to be honest I didn't look for that either... I'm heading outside to work on it again before it gets too warm, I'll give that a try.

BTW - here are three pictures, I'm hoping they'll be helpful:


BIG THANKS guys, I really appreciate the suggestions!!

1BAD02WS6

iTrader: (-1)

That's a twist in caliper!!! Your using the wrong tool! If you actually moved the piston in just by pushing it, you might have ruined the caliper

1BAD02WS6

iTrader: (-1)

You need Something like this... http://m.harborfreight.com/disc-brak...-pc-61381.html

V8Rumble

iTrader: (9)

Ahhhh, #%$@(%*... Thanks for letting me know, I'd never even heard of those before this weekend...

I'm guessing that the part that I circled in red is the tip-off that it's a twist-in caliper/piston??

therealcreeper

iTrader: (37)

Yes, that is the indicator that it needs to be twisted and compressed

Looks like you need to run to Harbor Freight!

V8Rumble

iTrader: (9)

Well, it appears that I MAY have dodged a bullet (either that, or the fact that I've learned to go slowly/take it easy when I'm not sure about the work I'm doing helped...).

I'm fortunate (?) enough to have a HF location fairly close by, so I bought the tool kit, & WHADDYA KNOW?!?! It's just amazing how easy it is when you're performing the correct procedure!!

Took the car out to an empty road nearby & did a couple of hard stops from 40 mph, then another from 50 mph, & finally a couple of hard stops from 60 mph. All of them performed as expected, no pulling to one side, no unusual noises, etc. I'll pay a little closer attention to how it stops over the next couple of days, but my gut's telling me that it's OK.

THANKS AGAIN for the help guys. I was really wondering WTH was going on...

01ssreda4

iTrader: (96)

As an an FYI, I was able to complete a brake job on calipers like this with channel locks, a c clamp, and some patience. The tool is optional but definitely helpful.

V8Rumble

iTrader: (9)

Oh yeah, I could definitely see that working - but by the time I learned the correct way to do it, I did NOT feel like "dinking around" with the pistons that way...!

The way that I did it when I was testing to see if the piston would rotate was to cover the piston with a shop rag so that my channel locks didn't put any scratches on the piston, then try to grip the piston itself (and not any of the rubber boot that it was sitting in) with the pliers & see if I could turn it - which of course it did easily. HOWEVER, between the angle I had & the large pliers I was using, I could only get about 1/8 of a turn out of it.

And given the fact that I had to make five or six revolutions to get the piston seated, I'm thinking that the $40 that I paid for that tool set certainly wasn't wasted. The job went really quickly & easily once I had the correct tool & followed the correct process.

THANKS AGAIN to all who corrected my understanding. I truly appreciate it.

"MAC"

iTrader: (1)

I had the same problem back in june. What i did was took a c clamp and forced it back and forth. Then pressed the brakes then repeat. After a bit i took a tire rod and a hammer and did the same eventually it worked just fine.