Chrysler 300C & SRT8 Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
217 Posts
Discussion Starter #1
It seems that one or both of the pistons in my offside front brake caliper is sticking and as a result the brakes are not releasing properly - therefore needs to be stripped down, cleaned up (possibly replacing pistons & seals) and then re-assembled. This was discovered when I took the car for an MOT recently; it was just mentioned as an 'advisory' and the car passed OK. Nothing is seized at the moment, the piston(s) are simply reluctant to retract of their own accord. The pads and discs seem to be fine but obviously I need to attend to it before things get worse.

When I used to ride motorbikes a few years back this was also a common problem - I never had to actually strip one of mine down fully and usually got away with just pumping the pistons out but not so far that they actually came out of the caliper, cleaning them with brake cleaner and a nylon brush (aka old toothbrush), using silicone grease to lube the sides of the pistons and all would then be fine until the next winter......

Has anybody else had this problem before on their 300C? If so, what's the best method and are there any tips, or issues that I need to be wary of? Is it likely that I will be able to get away with just cleaning rather than replacing? What's the best way to remove the pistons from the caliper?

All comments appreciated....

Dave
 

·
Registered
Joined
·
687 Posts
Might not be the pistons Dave, on mine the rubber boots had perished on some of the slide pins. I bought a service kit and all is well now.

Sent from AutoGuide.com Free App
 

·
Registered
Joined
·
687 Posts
I was lucky then. Gentle heat, WD40, and some mole grips eventually freed mine. Plenty of lithium grease on reassembly and hopefully it won't happen again.

Sent from AutoGuide.com Free App
 

·
Registered
Joined
·
773 Posts
It seems that one or both of the pistons in my offside front brake caliper is sticking and as a result the brakes are not releasing properly - therefore needs to be stripped down, cleaned up (possibly replacing pistons & seals) and then re-assembled. This was discovered when I took the car for an MOT recently; it was just mentioned as an 'advisory' and the car passed OK. Nothing is seized at the moment, the piston(s) are simply reluctant to retract of their own accord. The pads and discs seem to be fine but obviously I need to attend to it before things get worse.

When I used to ride motorbikes a few years back this was also a common problem - I never had to actually strip one of mine down fully and usually got away with just pumping the pistons out but not so far that they actually came out of the caliper, cleaning them with brake cleaner and a nylon brush (aka old toothbrush), using silicone grease to lube the sides of the pistons and all would then be fine until the next winter......

Has anybody else had this problem before on their 300C? If so, what's the best method and are there any tips, or issues that I need to be wary of? Is it likely that I will be able to get away with just cleaning rather than replacing? What's the best way to remove the pistons from the caliper?

All comments appreciated....

Dave
Had the same trouble with mine after 60k, I bought a set of second hand callipers which I sent off for refurbishment rather than having the car off the road as I found that I couldn't get genuine replacements in less than 4 to 6 weeks and the only other option was non standard callipers - which I didn't trust - at silly prices, nearly as silly as the price for the genuine article.
 

·
Registered
Joined
·
217 Posts
Discussion Starter #7
I'm pretty sure it is the pistons sticking on mine - the slide bolts seem to slide OK and their rubber seals seem intact. Careful application of a rubber mallet persuades the pistons to retract a bit which then allows the disc to turn freely, but the problem reappears once the brakes have been applied again. I have previously tried spraying the exposed parts of the piston with brake cleaner but this did not resolve it - I suspect I may need to try again and expose a bit more of the pistons first this time.....

If I remember correctly the 'silicone grease' which I used on motorbike calipers was also known as 'electrical contact grease' (e.g. used on battery terminals). Is lithium grease similar - presumably OK to use with the rubber seals and can withstand the heat that brakes will generate whilst in use?

If this fails, I see that Custom 300C shop sell caliper and piston seal service kits - has anybody fitted one of those before? If so what did you use to install the outer seals - I have seen mention in the LX service manual that a special tool is needed?
 

·
Premium Member
Joined
·
6,753 Posts
I have stripped the pistons and seals out of my mates and reinstalled with just my hands and a normal selection of tools. My mates pistons and calipers bores looked in perfect condition but still stuck when fully pushed home, once the pistons came out a few mm they were fine. It wouldn't have been an issue with slightly worn pads but I had just fitted new discs and pads.
 

·
Registered
2014 CRD
Joined
·
1,587 Posts
Haven't had a problem (yet) with my 300 but had the problem you describe with my PT. Had to strip the caliper out, replace seals and the caliper piston. Don't know if you can get these parts for the 300 or whether that's a new caliper job
 

·
Registered
Joined
·
147 Posts
yes had same problem with my pistons tried to clean them rub the down but still gave me grief ,only way to solve was new pistons and seals from the 300c custom shop job done no more problems
 

·
Registered
Joined
·
147 Posts
I'm pretty sure it is the pistons sticking on mine - the slide bolts seem to slide OK and their rubber seals seem intact. Careful application of a rubber mallet persuades the pistons to retract a bit which then allows the disc to turn freely, but the problem reappears once the brakes have been applied again. I have previously tried spraying the exposed parts of the piston with brake cleaner but this did not resolve it - I suspect I may need to try again and expose a bit more of the pistons first this time.....

If I remember correctly the 'silicone grease' which I used on motorbike calipers was also known as 'electrical contact grease' (e.g. used on battery terminals). Is lithium grease similar - presumably OK to use with the rubber seals and can withstand the heat that brakes will generate whilst in use?

If this fails, I see that Custom 300C shop sell caliper and piston seal service kits - has anybody fitted one of those before? If so what did you use to install the outer seals - I have seen mention in the LX service manual that a special tool is needed?
get the kits of the shop and use the garage I used in hernbay they will strip clean bleed and refit
 
1 - 11 of 11 Posts
Top