I’m looking for technical help or recommendations on: __ Stuck front driver’s side brake caliper.
So I recently had to fit a new battery as my old one had died. This was partly due to me not being able to drive my NC due to a seized front brake.
I finally managed to have a look at the caliper today…
First I checked the bleed nipple
A small amount of fluid came out but it didn’t free up the caliper.
I removed the 2 bolts holding the caliper in place but i couldn’t budge the caliper at all. As it’s my first time doing this I did the same thing on the passenger side and the caliper came away easily.
With the bolts removed I was able to move the slider pins backwards and forward with their rubber “boots” but no amount of effort would allow me to swing the caliper away from the disc.
Am I right to think I’ve eliminated the brake hose/fluid and slider pins as the cause of my problem? If so, does this just leave me with a piston problem?
The other issue I have is how do I actually get the calliper off? I can barely rotate the wheel by hand. I pushed and pulled but no joy. Is it acceptable to go at the caliper with a hammer? Is there something I can spray onto the caliper?
Apologies if I’ve missed something obvious, as I mentioned, im pretty new to this but keen to learn.
If the disc moves, then a big screwdriver to lever the caliper off, with a breaker bar on the hub to try and stop it moving. Least, that’s what I would try.
Don’t hit directly with a hammer use a bit of wood to dampen the blows.
Has the disc got a lip? If it has a seized piston the caliper isn’t going to ride over this. You may need to grind a section off to allow the caliper to exit.
Had this problem recently on my TT. Fortunately no lip so just brute force to get it off.
You can get cheap piston retraction kits off eBay etc. the little bars are useless on a seized piston. Cut it off and use, ideally, an impact wrench on the bolt head it passed through…. Mine didn’t have a bolt head so ended up having to buy a new caliper as I couldn’t move the piston…
They are newish discs and pads on the car, I fitted them , so there’s virtually no lip on on the discs.
No need for a brutal approach, probably a large flat screwdriver to ease the caliper off. Maybe stuck pads on a lightly rusted discs.
Thanks for the help so far and thanks for the very clear picture CBRDEANO.
Turns out I just needed to be a bit more forceful. Used a screwdriver to pry the caliper away.
The lower slider pin was very slow/ unwilling to move but there was also signs of rust under the rubber on the piston so I’m going to take the caliper off completely and give everything a good clean then replace the pins and piston before re fitting.
Happy to report that the disc and pads seem to be fine. No signs of heat damage and plenty of life left in them.
Couple of quick questions if anyone is still reading:
When I remove the caliper and “crimp” the brake hose (bought a special tool!) how long can I leave the hose crimped whilst I clean the caliper? Obviously the quicker I can re fit the caliper the better but would a couple of days be ok before I risk damaging the brake lines?
Obviously I’ll loose some brake fluid when I remove the caliper, am I right in saying I just need to top up the brake fluid once the caliper is re fitted?
Now I (sort of) know what im doing im hoping to check all the brakes in the new year when the weather improves so I’ll drain / replace the brake fluid then.
A small trick for helping retain brake fluid is to use a thin plastic bag.
Open the reservoir top - place the plastic bag over the opening - replace the top.
If I am keeping calipers off for any amount of time I use an M10 nut and bolt through the banjo hole to seal the system. ( I also have quite a few copper washers in the garage - they should only be used once )
I’m not a fan of crimping any brake line. If they are old just the act of squashing them may be the straw that breaks the camels back. I’d take Deano’s suggestion to inhibit the flow in some way.
You can block the end with blue tack. As long as you have unscrewed the master cylinder cap, any pressure will be just gravity.
Belt & Braces. When I did my TT NS front I had a slight surge that suggested there was some pressure in the system. Maybe the ABS? Anyways you can only go on your own experience. Maybe relevant or not.
Have you tried pushing the piston back a little, grease the slide pins (red rubber grease) then refit everything then go for a drive?
Sticky pistons can be eased and can be ok, sometimes they will need replacing/a refurb also.
Just a suggestion, I’d try first.
These cars calipers don’t need any encouragement to seize, keep them operating, serviced/lubed or they cause trouble. Best replaced if it gets to that with an OEM caliper or refurbished of the same.
A quick update (sorry for the delay, Christmas and all…).
Removed the caliper, replaced the pins ( they looked ok but as i’d bought replacements I thought I may as well use them).
I wasn’t able to push the piston out by applying pressure to the brake pedal. Not sure if that’s a common issue?
I put the caliper in a vice and finally managed to get the piston out which certainly had signs of rust (see photo).
Installed a new piston amd put everything back together. Took the car out for a test drive and everything seems ok. Checked the brake fluid level a few times on the way as well as a few checks on the temperature of the caliper/ brake disc and all 4 corners were the same temp so hopefully that’s sorted it. Then came Christmas, then came snow so I’ve not been able to drive it since.
Thanks for all your advice, I’m hoping everything runs smoothly until the weather improves a little then I plan on looking at the other 3 corners to hopefully avoid this happening again.
