Compressing the piston on Eldorado calipers - Diesel Forum

spaceballs · 06-10-2007, 12:29 AM

I was not too impressed with the quality of brake pads that came on the kit from Blackbirds. I found some semi metallic pads from Autozone and I am trying to put them on now. I am having a lot of problems compressing the piston on the caliper. Is there something that I am missing. I am really cranking on my c-clamp and it is not budging. Does this 76-78 Eldorado caliper have a different kind of piston in it or something or is there some trick to getting it to compress. I have to drive somewhere tomorrow, and I would rather take my truck. Any ideas on getting this thing to go back in?

Thanks for the help.

BlueMule · 06-10-2007, 12:50 AM

I dont know but I wonder if the ABS valve has some type of checkvalve that's keeping the fluid from returning to the reservoir. You might try opening the bleeder valve so the fluid has somewhere to go. [img]/ubbthreads/images/graemlins/shrug.gif[/img]

budman451 · 06-10-2007, 01:03 AM

Does that caliper have the parking brake cable built into it? If it does you may need the tool to turn the piston in, you do not want to crank on it with a C clamp, that would be a good way to ruin it. If there is no park brake on it, you may have a collapsed brake hose or bad proportioning valve that is not allowing fluid back, but it is generally good practice to crack the bleeders loose when pushing the pistons in so the old fluid does not get pushed back through the hoses/lines/valves. Here is a pic of the tool you may need, they are available through nearly any parts store.

Buddy

spaceballs · 06-10-2007, 01:17 AM

I did open the bleeders up but the thing won't go in.

It does have a parking brake on it. Does that tool just go into the holes on the piston and then it is used to just screw it back in? That may be it. How hard is it usually to get this piston back in?

Renegade · 06-10-2007, 08:04 AM

I sent you an e-mail as I just saw it & hadnt been on in a while.

It takes some finnese (ratcheting) of the e-brake lever to get the piston back in. I had a heck of a time the first time as I could get it to ratchet the piston out but not back for my new pads. Seemed like I even had the e brake lever off to help get the piston back in a lil quicker.

Cheers

tjbeggs · 06-10-2007, 08:54 AM

Buddy_M is right on. The parking brake uses threads inside to actuate the parking brake so when pushing the caliper back in you need to rotate the piston while pushing it back in. There should be no need to move or remove the parking brake lever.

**edieedie** · 06-10-2007, 12:37 PM

open the bleeder, and take 2 big box end wrenches that will just slip in between the pads and squeeze, and will move the pads all the way back

spaceballs · 06-11-2007, 12:01 AM

I undid the bolt on the parking brake lever and the piston just fell out. Ouch. Brake fluid everywhere...a complete mess. I had to leave town and head to work so I ended up taking the old lady's truck and I am going to have mine towed to a shop nearby. Once it came apart I saw with perfect clarity how it would have gone back together. Twist the piston and push it back in. I will pick it up soon and keep this in mind for next time.

I have to do the fronts sometime soon also. Is there anything I need to know about compressing those pistons on the calipers?

tjbeggs · 06-11-2007, 01:29 PM

for the fronts just open the bleeder and use a c-clamp or similair to push the piston back in. But those rear so need to be "thread" back in while pushing in.