Should I replace the piston? - Updated

[monkeymax]

Right, started the job of refurbing my old and not working rear caliper tonight. Apparently the refurb kit has arrived but I've not had time (when the post room has been open) to go collect yet, so I couldn't do the whole job.

However, when I removed the piston on the caliper I noticed it had a bit of rust around it and was a bit scratched. I got the rust off fairly easily but it's not in pristine condition.

In the Haynes manual they recommend replacing both the caliper and the piston if there's any sign of rust or pitting on the piston. Obviously replacing the caliper (again) is not really an option else I wouldn't be refurbing it! However, should I really worry about replacing the piston as well? It's not a big deal; £12 from Brakes Int I think. Problem is it's now Bank holiday which means I'd have to wait yet another week until I can fit the brakes to the car due to having to wait longer for delivery etc... But I don't want to refurb now and replace just the piston later on as this would mean new seals again, I guess?

I have a photo or two of the piston (I was photographing everything to do a KB article but have noticed there's photos and description in the Haynes manual so probably won't bother now) so if anyone needs a visual of the piston, just say on here. The camera's battery should be recharged by the morning.

Cheers,

Max

[MartG]

Is the rust on the inside or outside of the piston seal. If its on the inside part ( i.e. the bit furthest in to the caliper ), definitely replace it.

[Ad Mayo]

I had a rusty piston on my civic the rubber gaitor had split letting water and crap in. Cleaned the piston up as best I could, replaced the rubber gaitor and it was fine I think it would last a while like that but I would change it to be on the safe side.

[kevin..in]

I'd just order some new calipers and sell your seal kit on ebay
that way you know you wont have to do it again for a long while!

[monkeymax]

Thanks for the replies. After having another look at the piston, it'll be a new pair then...

I'd just order some new calipers and sell your seal kit on ebay
that way you know you wont have to do it again for a long while!

At £84 for one and £93 for the other, that's a serious amount of money. I did consider it, but figured it'd make more financial sense to refurb the current set. Don't know, do you really think it's worth spending upwards of £200 (once you include postage) on a new set of rear calipers?

[monkeymax]

Righto, time for an update. I didn't manage to do anything with my caliper until today due to a huge short-term uni project.

I ordered the pistons from Brakes International and opened them up this afternoon, noticed they're not correct!!! The internals of the pistons were different to the actual ones off the brakes off the car. So they wouldn't screw onto the caliper.
Now I realise that I may have been missing something with the pistons, but basically they had not thread in them and it looked as though they were designed such that you remove the internals from the old pistons and put into the new ones. But I couldn't figure out how you get the internals out the old ones.

Well, my MOT is booked for Tuesday and frankly I don't think I can hold off much longer if I still want to make the MR2 World Record attempt at the end of the month - it's either this week or I don't go.

So I cleaned up the old piston from one of the other calipers I had - polished it with wet and dry 1200 I think. Not much at all, just enough to get the crud on the surface off.

Cleaned off the caliper and put everything back together. I think.

Right, here's the question. When I started off, I had the following items in the recon kit:



Then when I finished, I was left over with the following (i.e. unused):



Is that correct? I assumed that these kits could apply to a different car as well it could have other parts...?
Last time I did this job on these calipers I also didn't use these parts; but that wasn't a full "take off car and refurb" job. Plus, I had another caliper next to me with all the seals still on and couldn't see where these were on that one... soooo...

Basically, before I put the car through MOT, have I forgotten anything?

Cheers!

-Max


Edit: Before someone says that I'm not supposed to do that to the old piston and it's not a good idea, etc, I'm on the phone to Brakes Int on Monday to find out what's going on. I'll either get a new piston and swap over, or I'm thinking I may even just give in and go get fully reconned calipers direct off them. Expensive, but given how this caliper still looks dirty and mucky, in spite of hours of cleaning and wire brush applications... I'm beginning to think the extra money may be worth it....

[eRATic]

Max, pretty sure i have a pair of rear calipers that are ok in the garage. if you get stuck pop round or give me a call.

save your money for the corrado conversion.

[monkeymax]

Max, pretty sure i have a pair of rear calipers that are ok in the garage. if you get stuck pop round or give me a call.

save your money for the corrado conversion.

LOL - thanks!
May take the spare clutch off you if you end up not using the 1b one as well!

[monkeymax]

First off, many thanks for the phone call this morning Tom! You were right - I did indeed miss that seal. But the old seal was actually in very good condition; still... changed it.

Secondly:

Jobs a good 'un! Not only does she drive now, but she stops too! Woohoo! The handbrake holds just fine. The whole procedure today was simple and quick - wish it had always been as good as today, but then I did all the prep beforehand to make sure!
No more curse words, but after all the aggro we've given each other, we made up for it - gave her a good old wash and clean (covered in dust from the garage over the months). It's so rewarding to sort out the car so that it's driveable and clean again!

Before tucking the old girl away again, I made sure she was psyched up for the MOT on Tuesday - pointed out I've become more active on Two Brutal and if she fails I may start practising with a Two Brutal hammer (an angle grinder)...

Think she'll pass...

Fingers crossed.

[Icsunonove]

First off, many thanks for the phone call this morning Tom! You were right - I did indeed miss that seal.

No problem Max, glad to be of assistance.

Glad you've got it sorted now

[monkeymax]

I know that probably no-one but me cares, but the '2 passed the MOT today first time. According to dad, flew threw with no advisorys.
Obviously I'm pretty happy and can't wait till the weekend when I get to pick it back up and drive it home!

I'll put together a brief KB article about the refurbing of the calipers if anyone is interested in it...?

Also, I've got Brakes Int. investigating the pistons as even they agree they seem to have the wrong item on their catalogue at the moment...

[MartG]

the '2 passed the MOT today first time.

So when's its first trackday

[monkeymax]

So when's its first trackday

LOL! If you'd asked me a few months back I'd have said never as it's too good. I'm now leaning more and more towards saying "sod it" and throwing it around a track.

Should probably sort out the suspension and bushes first though (if I can afford). When I drove it the other day it was feeling a bit... wobbly, so obviously the months of not moving have done the already tired suspension no favours at all...

[liamc]

[quote="monkeymax"]I ordered the pistons from Brakes International and opened them up this afternoon, noticed they're not correct!!! The internals of the pistons were different to the actual ones off the brakes off the car. So they wouldn't screw onto the caliper.
Now I realise that I may have been missing something with the pistons, but basically they had not thread in them and it looked as though they were designed such that you remove the internals from the old pistons and put into the new ones. But I couldn't figure out how you get the internals out the old ones.
quote]

Anyone know how to get the threaded part out of the exsisting rear piston?
I've just hit exactly the same problem. Thought they were the wrong pistons, then looked on the EPC to find that pistons and the internals are sold as seperate parts so I guess they must be removeable.

Edit: I'm now sure they are the wrong pistons.