TR2/3/3A Can a caliper be freed up without a rebuild?

[B1620]

I believe I have a stuck caliper that is causing my 59 TR3A to pull to the right. Is there any way to free the caliper without doing a rebuild? There is no leakage around the piston.

 

[TomMull]

I believe I have a stuck caliper that is causing my 59 TR3A to pull to the right. Is there any way to free the caliper without doing a rebuild? There is no leakage around the piston.

Not my experience. If you do manage to get it free, then it will usually leak. I'd plan to rebuild it with a new piston. You should pull the wheel to determine what is or is not stuck. Tom

 

[TR3driver]

You can try removing the pads and prying between the pistons & rotor to retract the pistons. Use care to avoid damaging them. If you can force both pistons to retract, put the pads back in and step on the pedal several times to work them back out. Sometimes that will free up a piston that is only slightly stuck.

But I mostly agree with Tom, if you do get it free it will probably leak.

 

[TFB]

Not my experience. If you do manage to get it free, then it will usually leak. I'd plan to rebuild it with a new piston. You should pull the wheel to determine what is or is not stuck. Tom

I would suggest you rebuild both.Parts are resonable,old caliper bodies should be reusable as the bores only hold the seal,
and one major leak will while driving will have you grabbing the emergency brake handle in a panic ,unlike a modern car with dual circuits.
Tom

 

[Got_All_4]

Use stainless steel pistons when you rebuild the calipers and flush your system then go to DOT 5 brake fluid or you will have the same problem in a few years. Stainless steel resists corrosion and DOT5 does not absorbs moisture like DOT4 does which corrodes standard pistons.
Had that same problem in my TR3. Beginning of each spring driving season the car would pull to one side then slowly work it's way out as I drove it. Every year it took longer till one year it was stuck. I used a "C" clamp to push it back in but started to leak shortly after that.

 

[TR3driver]

IMO the SS pistons are overkill if you're switching to DOT 5. The calipers I'm running now had new seals installed back around 1985, still original pistons, and they are working fine. All I've done in the intervening years is change pads. I was really surprised that the bleed screws weren't even stuck, when I moved them from the wrecked TR3A to the current TR3 in 2008.

 

[titanic]

You can try removing the pads and prying between the pistons & rotor to retract the pistons. Use care to avoid damaging them. If you can force both pistons to retract, put the pads back in and step on the pedal several times to work them back out. Sometimes that will free up a piston that is only slightly stuck.


Probably just me, but I would be very hesitant to pry against a rotor as it would be very easy to bend it a few thousandths.
Also, when replacing the pistons, I would spring for SS ones( along with dot. 5). I know that Moss sells rebuild kits with steel pistons for about $27, but would rather do the job once and forget it. Maybe moisture isn't as much of a problem in So. CA compared to OR.
Berry

 

[sp53]

Sometimes if the pistons is frozen you can stick in a pad that is worn down some and press the brake to see if the piston moves out. If not, I would try and squeeze it back some with a clamp then push the piston out with the brake pedal . Either way, I would be seriously thinking about a full rebuild. Look on the forum history for caliper rebuild because it is a well-travelled path.