I'm a first timer replacing (front) brake pads in my Nissan Pulsar 1.8 (hatch).

I had problems removing the caliper bolts on both sides - after successfully removing them, I removed the old pads and only tentatively replaced the bolts for further work the next day (Today).

Today I affixed the new pads for the right side and started pumping the brakes - whilst doing this, I heard some squirting.

On the left side I noticed a lot of brake fluid having leaked. I'm not sure if this has anything to do with having the bolts only loosely screwed in? There isn't any damage to the brake line as I properly suspended the caliper making sure no kinks or damage was to occur.

The caliper on the left side was covered in fluid - I thought it would still be possible to at least get the new pads in. Using my C-clamp, I wasn't able to push the piston back; it would seem as thought it was stuck. Therefore, I disconnected the brake line, thinking it might have something to do with pressure? Having the caliper completely disconnected, I re-attached my C-clamp and screwed it in as far as possible. Now the C-clamp seems to be stuck in the caliper (reading now, I should have used a wood block or one of the old pads rather than screwing the C-clamp directly into the piston), the screw top rotates, but doesn't move the screw shaft. I'm thinking this might be due to the brake fluid on the clamp acting as a lubricant, any ideas on how I might unstuck it?

Any tips for any of the questions highlighted?


Stuck piston

The removed C-Clamp

2 Answers 2


Firstly, You should not pump the brakes with any of the pads missing - as you have discovered, this results in the pistons being forced out of the calipers! You probably then found that the piston wasn't quite square in the caliper, and re-settled once you had removed it.

I take it you have now removed the offending caliper from the car? (if not, do so now that you have disconnected the brake line). From the way I read your question, the thread of the clamp is stuck? Without seeing it or knowing the design of the clamp you're using, it is difficult to suggest a solution here - most c-clamps I have used have the screw handle and shaft as one casting, so turning the handle would always unscrew the shaft. Can you try getting a grip on the shaft with a pair of mole grips / stilsons or similar and turning it with them?

Once you have removed the clamp, it is vital to remove all traces of brake fluid from anywhere it shouldn't be - it will very easily contaminate the pads and result in the brakes failing. It also makes a very effective paint stripper if it gets on the car bodywork. The caliper should then be cleaned very thoroughly to prevent any dirt getting in it, reassembled and bled properly (including bleeding the other side and the rear brakes, in the correct order and using the correct type of fluid, both of which will be specified in the workshop manual) to make sure there is no air in the system - the fluid must come from a new, sealed bottle to ensure there is no contamination, and you should bleed the system through fully to replace the old fluid.

As you are a first timer at brake work, If you are in any doubt as to how to go about any of these jobs, I would suggest that you take it to a professional to sort this problem, as brakes are too important to risk. You should be able to change pads easily in the future now that you know what not to do however!

  • thanks for the insight! I finally got the C-Clamp out of the caliper - see the attached pictures. Now I need to get the piston in some how...
    – wulfgarpro
    Apr 4, 2012 at 9:47
  • so, now that I have successfully removed the clamp, should I re-attach the caliper and the old brake pads?
    – wulfgarpro
    Apr 4, 2012 at 10:52
  • Ok, so now you need to clean up the exposed part of the piston, then carefully wind the piston back in (using, as you noted, an old pad to protect it). Refit using the same pads as the other side (i.e. new if the other side has new ones), then fully bleed the system.
    – Nick C
    Apr 4, 2012 at 12:32
  • Be very careful not to snap any of the bleed screws in the process - they can easily sieze and break, which will wreck the caliper. A small quantity of penetrating fluid can help here. I'd also sling that c-clamp and get a new one, it looks fairly ruined!
    – Nick C
    Apr 4, 2012 at 12:33
  • so, I bought a new c-clamp... using an old pad, it doesn't seem like it's possible to get the piston to move back into it's housing. I thought it might be possible to bolt up the caliper with the old pads and have someone press on the brake... but the piston is so far out (see picture above) that the old pads no longer fit. Any ideas?
    – wulfgarpro
    Apr 6, 2012 at 2:16

It's possible that you reached the end of the threads and went past them.Try pulling the c clamp handle while turning and maybe it will catch and unsrew itself.


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