Tried to change brake pads, can't push piston back!! Seized or collapsed brake line

D_Nyholm · 11-06-08, 11:20 AM

I was changing my rear brakes the other day and I changed the drivers side fine. WHen i went to do the passenger side, the piston would not budge no matter how hard i tried. I took the cap off the master cylinder, took out some HUGE 20" Channel locks and still couldn't get it to budge. I asked a friend who said it could be that the line is collapsed and won't allow the fluid to move back. I am thinking I just need a new caliper, but i'd hate to get a new caliper and have it be the lines!!! Any ideas?

Blackend · 11-06-08, 11:24 AM

If you're using channel lock pliers, you've probably just bound the piston by only applying force to one side of it. The piston has to be pushed directly back into the caliper, any additional force on one side of it will cause it to bind up and not go back into the caliper. Try getting a big C-clamp and then using the plate from the old brake pad to push down directly over the piston.

D_Nyholm · 11-06-08, 11:28 AM

I thought the same thing so I made sure they were pushing back perpendicular to the piston face. They are HUGE, pretty easy to make sure they push back straight. The other side was cake, didn't even have to push hard.

I'll give it a shot with a c-clamp and old pad to see if I can get it to go that way. If I really clamp it tight, can anything else break on it?? Or I would just need a new caliper anyway?

whats77inaname · 11-06-08, 11:32 AM

Just go to Autozone and get a brake caliper compressor tool. They're like $9.00, and easy to use, and you don't have to worry about uneven pressure on the piston.

kotetu · 11-06-08, 11:39 AM

Autozone charged me $37 to borrow it but refunded me 100%.

whats77inaname · 11-06-08, 11:42 AM

Quote:

Originally Posted by kotetu

Autozone charged me $37 to borrow it but refunded me 100%.

Really? I picked up my unit from them for $9.xx on the recommendation of a friend of mine who used to manage a brake shop. I'll see if I can find a pic.

Edit: Ah, here we go. It's called a "disc brake pad spreader". $9.99 @ JC Whitney.

antik · 11-06-08, 02:02 PM

My "disc brake pad spreader" looks like this:

BigRed · 11-06-08, 02:48 PM

I did mine with a 6" C-Clamp with absolutely no problem. Both sets of rear pads took me 15 minutes...the easiest brake job I've ever done.

MarcD · 11-06-08, 03:05 PM

Quote:

Originally Posted by whats77inaname

Really? I picked up my unit from them for $9.xx on the recommendation of a friend of mine who used to manage a brake shop. I'll see if I can find a pic.

Edit: Ah, here we go. It's called a "disc brake pad spreader". $9.99 @ JC Whitney.

If he can't get it back in with a large C Clamp, there is no way that 'official' tool is going to work. I have one of those and they work fine but no where near as powerful. You most definitely have a collapsed brake hose. I have had that happen in the past. Easy to change out. Did you notice your brakes pulling or dragging on you?

reboticon · 11-06-08, 03:50 PM

Sooo... you guys know you are supposed to loosen the bleeder screw and then push back the piston, right?? Simply taking the cap off the master= big no no. Its ok to do on Pre-ABS cars, but improper procedure is the number 1 killer of ABS units..

whats77inaname · 11-06-08, 04:01 PM

Quote:

Originally Posted by MarcD

If he can't get it back in with a large C Clamp, there is no way that 'official' tool is going to work. I have one of those and they work fine but no where near as powerful.

Hmmmmmm, I dunno, man. I've never had an issue using that, and it has always been all the force I need. I wasn't suggesting it as a method to solve *his* particular problem, more like an addendum to Blackend's post about making sure that the piston is put back into place while exerting equal amounts of pressure across the piston.

sap · 11-06-08, 04:32 PM

Quote:

Originally Posted by reboticon

Sooo... you guys know you are supposed to loosen the bleeder screw and then push back the piston, right?? Simply taking the cap off the master= big no no. Its ok to do on Pre-ABS cars, but improper procedure is the number 1 killer of ABS units..

Seriously? I could have used this a week ago before I changed my rear pads, don't know what made me think Haynes could be trusted

Haven't been greeted with an ABS light anyway.

3.2legend · 11-06-08, 05:19 PM

Quote:

Originally Posted by reboticon

Sooo... you guys know you are supposed to loosen the bleeder screw and then push back the piston, right?? Simply taking the cap off the master= big no no. Its ok to do on Pre-ABS cars, but improper procedure is the number 1 killer of ABS units..

Loosen the bleeder screw to the brake caliper? You mean so that air wil get in the system and then you will have to bleed the system afterwords?

Sounds like a bunch of bullshit. Ive dont lots of brake jobs on abs cars to never have anything go wrong with them and i just took off the master cylinder cap so the fluid wouldnt spill out.

I would like an explanation for your logic on this.

3.2legend · 11-06-08, 05:22 PM

Quote:

Originally Posted by D_Nyholm

I was changing my rear brakes the other day and I changed the drivers side fine. WHen i went to do the passenger side, the piston would not budge no matter how hard i tried. I took the cap off the master cylinder, took out some HUGE 20" Channel locks and still couldn't get it to budge. I asked a friend who said it could be that the line is collapsed and won't allow the fluid to move back. I am thinking I just need a new caliper, but i'd hate to get a new caliper and have it be the lines!!! Any ideas?

Hey man, do your caliper pistons have slots (grooves) in them? If they do, then your supposed to put somehting in there and turn them in instead of pressing them in.

daddykay24 · 11-06-08, 05:44 PM

Our calipers are known to freeze up. So if none of the above ^ methods are working, just replace the caliper. I just had to do this myself because one was frozen, so I changed both of them.