Front piston came out of boot, can't get it back in, do I need the boot to be on?
03-26-2016, 01:44 PM
#1
Front piston came out of boot, can't get it back in, do I need the boot to be on?
In process of doing a complete brake/wheel job: rotors, pads, brake fluid flush, wheel spacers, and wheel painting for all four wheels.
After removing the old pads, I used the caliper tool to push in the front passenger's side piston (second furthest from the master cylinder which is just in front of the driver's side in front).
A minute or so later, the same piston had popped back out even slightly further than when I started.
I used the caliper tool to push it back in but it only went a couple turns then wouldn't budge.
I took the caliper tool out in search of a large C-clamp and when I came back a couple minutes later, the piston was all the way out of the caliper hanging by the rubber boot.
I tried to get it back in but the fit was extremely tight. Then when I finally got it "set" and started to push, brake fluid started coming out of the boot area. More brake fluid came out and popped the piston out of the boot.
The boot has a groove both on the end of the piston (the end closest to the pad) as well as a groove on the caliper. I haven't been able to find a way to get the boot in both grooves at the same time.
In other words, if I put the boot in the caliper, the piston won't shove into the boot at all. If I take the boot out and put it on the piston first, the fitting is too tight to use a flathead to force it into the groove on the caliper.
Has anyone here been able to solve this issue? Or maybe a better question is if I even need this boot at all?
btw this is for an Audi A4 B6 but since those forums are neither active nor have info on this I figured I'd post (same concept) here
After removing the old pads, I used the caliper tool to push in the front passenger's side piston (second furthest from the master cylinder which is just in front of the driver's side in front).
A minute or so later, the same piston had popped back out even slightly further than when I started.
I used the caliper tool to push it back in but it only went a couple turns then wouldn't budge.
I took the caliper tool out in search of a large C-clamp and when I came back a couple minutes later, the piston was all the way out of the caliper hanging by the rubber boot.
I tried to get it back in but the fit was extremely tight. Then when I finally got it "set" and started to push, brake fluid started coming out of the boot area. More brake fluid came out and popped the piston out of the boot.
The boot has a groove both on the end of the piston (the end closest to the pad) as well as a groove on the caliper. I haven't been able to find a way to get the boot in both grooves at the same time.
In other words, if I put the boot in the caliper, the piston won't shove into the boot at all. If I take the boot out and put it on the piston first, the fitting is too tight to use a flathead to force it into the groove on the caliper.
Has anyone here been able to solve this issue? Or maybe a better question is if I even need this boot at all?
btw this is for an Audi A4 B6 but since those forums are neither active nor have info on this I figured I'd post (same concept) here
03-26-2016, 02:55 PM
#2
Yes, you very much need that boot, it prevents dirt and debris from scoring your pistons/cylinders, and keeps brake fluid from dripping out into your rotors/pads/driveway. I can't say I've ever had any problems getting both ends in their grooves.
I have both B6 and B5 Audis, and you only need the caliper tool that rotates the piston on the rear. The rears auto-adjust for parking brake consistency, where the fronts operate in a conventional fashion and can be compressed normally.
It sounds like you applied pressure to the system with multiple calipers unmounted, which will cause the pistons to pop out. Only operate on one corner at a time.
There should be a writeup on AZ that covers the procedure.
I have both B6 and B5 Audis, and you only need the caliper tool that rotates the piston on the rear. The rears auto-adjust for parking brake consistency, where the fronts operate in a conventional fashion and can be compressed normally.
It sounds like you applied pressure to the system with multiple calipers unmounted, which will cause the pistons to pop out. Only operate on one corner at a time.
There should be a writeup on AZ that covers the procedure.
03-26-2016, 09:01 PM
#4
first off thanks for the prompt replies.
I got the boot back on by first putting it over the piston and sliding it all the way down the piston. then with the piston still loose I put the other end of the boot into the caliper groove. I shoved the piston into the caliper pretty far and pulled the boot into the groove of the piston.
thanks again
I got the boot back on by first putting it over the piston and sliding it all the way down the piston. then with the piston still loose I put the other end of the boot into the caliper groove. I shoved the piston into the caliper pretty far and pulled the boot into the groove of the piston.
thanks again