Volvo RWD 120-130 Forum

Hi,

Just a quick question - following an incident with a smoking caliper I decided that a rebuild was on the cards. I've stripped the first caliper and found pitted pistons, a little gunge and some rust on the lip between the o ring seal and the lip of the cylinder. Is it ok to clean this up with something like 1200 grade wet and dry sandpaper (with a thorough clean afterwards) or is there a better way of going about this? Its a single circuit system so I'd like to get it right first time. I haven't split the caliper - just removed the seals and pistons.

Thanks in advance for any suggestions and comments,

Aidan
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1967 131, 1969 131, 1973 Triumph GT6, 1972 Triumph Spitfire 2.5

I have never had any success bringing a bad piston back to life. I wouldn't bother trying.

Dean

...just about impossible!...that's because when they corrode, the chrome plating flakes off, and a pit underneath results...and the seal doesn't have the compliance to reach into that pit to seal it...so I agree, if the pistons are pitted, they're toast and need to be replaced...and to do that, SS, which will never again develop pits sound pretty good to me to do that! Polishing and rechroming may be a possibility, but pricey (unless you BIL has a plating business).

Cheers

I've managed to find new pistons so I'll put them in along with new seals - they're not SS but they'll keep me going for the next few years at least. I've cleaned up the cylinders with wet and dry sandpaper - just a bit of surface rust - nothing too major. Have to replace the pads too as the overheating caused them to break up - the disk/rotor seems to be ok - I've put a dial guage on it and it seems to be straight enough.

Thanks for the responses and thanks to Ron for the suggestion on his Swem site about using hydraulic pressure to push the pistons out - it made life a lot easier.
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1967 131, 1969 131, 1973 Triumph GT6, 1977 Volvo 245 DL

Where did you find them and what did they cost?

Hi,

I got them from CVI Automotive - they sell a kit for 870 Swedish Kroner. They also sell rebuilt calipers but they'd be costly in terms of shipping (especially as you have to send back the originals).

As you're based in the US I'd imagine that it'd be cheaper for you to source them
from a Volvo specialist there - the stainless steel ones from John Farrel in NY that Rhys mentioned seem like a better long term solution.

Aidan
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1967 131, 1969 131, 1973 Triumph GT6, 1977 Volvo 245 DL

This guy?

http://www.fortunecity.com/silverstone/tread/1046/id23.htm
--
1967 131, 1969 131, 1973 Triumph GT6, 1977 Volvo 245 DL

You can do anything you want to clean the bores and the seal grooves, but the pistons must be perfect, and if they are pitted they must be replaced. Stainless ones are available from John Farrel in NY, and I have used them on many cars to great success.