Front brake inboard pistons

[4RunnerConvert]

I've done many brake jobs over the years but never on a 4 runner. 4 runner rear brake went without a hitch but the fronts were a different story. When I try to compress the pistons into their cylinders, the inboard cylinder will not retract completely. They get stuck about 1/8 inch out. (Outboards compressed fine). This is preventing me from installing a new pad on the inboard side.

Is there a trick to getting them fully retracted? Must I turn them like some rear GM brakes? I tried opening the bleeder valve but it did not help. Something is holding them other than the brake fluid.

Suggestions?

 

[DocMT]

The 4th gen was plagued with frozen pistons in the front calipers. There are probably a thousand threads on this. I believe the 5th gen used the same exact carryover calipers, so it's just a matter of time before we see 5th gen owners complaining of frozen pistons in their front calipers too.

You might be the first one. My guess is that your pistons are just starting to get stuck. Since they are not badly frozen (based on the fact that you were able to move them), you might be able to save them. If I were you, I'd disconnect the brake line from the caliper and use compressed air to blow the pistons out of their bores completely. Then clean up the pistons/bores as good as you can before re-installing them.

 

[4RunnerConvert]

Thanks for the reply

Well it seems I posted to the wrong generation as this is a 2005 4th generation. With your information, it's no wonder that the dealer wanted $400+ an axle. As for saving them, I think I will just get some re-mans for it. $125 each. Dealer wanted $375 for new. I don't want to mess with the seals or reuse them once I pull it apart. Stopping is way more important than the few bucks for re-mans.

I may pull them apart just for fun to see how bad they are. Maybe I'll take pictures.

thanks for your feedback

 

[DocMT]

Well it seems I posted to the wrong generation as this is a 2005 4th generation. With your information, it's no wonder that the dealer wanted $400+ an axle. As for saving them, I think I will just get some re-mans for it. $125 each. Dealer wanted $375 for new. I don't want to mess with the seals or reuse them once I pull it apart. Stopping is way more important than the few bucks for re-mans.

I may pull them apart just for fun to see how bad they are. Maybe I'll take pictures.

thanks for your feedback

Oh, yeah....a 2005 4Runner is pretty much expected to have this happen. I'm surprised it hasn't happened sooner.

I went the same route as you...got remans and they've been fine so far. That was about two years ago. But I expect them to seize again eventually...

 

[Uneek]

Well it seems I posted to the wrong generation as this is a 2005 4th generation.

Moved to 4th gen sub-forum.