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Rave's Motors - 12/4/19 ST170 Step 1: MOT Step 2: Profit

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Thanks for the helpful pointers all :) .

 

Easy job. Clamp flexi,Slacken the caliper to carrier bolts, slacken union, then undo the previous bolts, then spin the caliper off the flexi. Then bleed off, a eezibleed is about a tenner on trade usually, if your working on your own.

Wouldn't fuck about with the piston, it'll more than likely leak anyway, the plating usually comes off and fucks the seal.

 

Going by the pictures, replacement calipers come with the carrier- the caliper to carrier bolts are those funny 5 sided ones that I've seen other people asking about...and mine look shagged, I'm not sure they'd come off even if I had the proper socket, which I don't!

 

I think what I'll do is just rub the piston down and shove it back in slathered in red rubber grease, just to get me mobile. It should last a 100 mile round trip if I'm careful, I reckon. In the meantime I'll order a couple of caliper refurb kits from Bigg Red or similar, about 32 quid for both calipers, then will do the lot when I change the discs and pads on the other side (I'll grease both sets of sliders this weekend, though).

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Another update. I unexpectedly had this afternoon free so despite having stood in a muddy field marshalling a MTB race for most of the morning, I jacked the car up and set about the caliper. Initially it went well, the bolts came undone easily and I found copious amounts of copper grease on them, so I was reasonably hopeful. Got the pads out and the disc off no bother. I then had a go at the piston with some wet and dry, got it feeling reasonably smooth, gave it a clean with some antiseptic spray as I couldn't find my can of brake cleaner, gave it a good coating of red rubber grease...and couldn't even begin to move it. I've tried various ways of levering it back in, the most promising of which was jamming in a pair of pliers and trying to use them as a wedge between the piston and the carrier, but it ain't going anywhere.

 

It got dark at that point so I put the wheel back on, brought my tools in and came here to seek further advice. As in the pic I posted above, the piston is in poor condition all the way round. The dust cover has either come loose or was never installed properly in the first place, which I guess is why. I know almost nothing about brakes, but I assume that the piston is designed to go back in when pressure is applied to it, otherwise they wouldn't release?

 

The only way I can see that I'm going to be able to move it would be to buy or make a tool with a screw thread to force it back in. I see that you can buy such a tool easily enough, but I thought they were designed for winding in calipers with an integrated handbrake function. Am I just being an idiot trying to get the piston back in with a bit of leverage? And if I can force it back in, is the caliper likely to work as well as it did before, IE OK but obviously binding a bit? I have ended up sailing too close to the shite wind and the pug was my last remaining working car, and I'd promised my in-laws I'd pick them up from 40 miles away on Tuesday. I know I'll need a new caliper or a complete rebuild afterwards, just wondering if the car can be bodged in the meantime just to get me mobile. I do realize that brakes are important, so if there's no safe way of doing it, I won't!

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OK thanks, guess I'll give the in-laws the bad news that they're coming home on the train then! :(

 

I already gave the flexi a dose of plusgas where it meets the caliper, but I suspect that will be the next bit of grief. What would I use to 'clamp it off', mole grips or a g-clamp maybe?

 

Edit: Does it damage the rubber if you leave them clamped for a few days? Since I don't think I have any other jobs lined up for the car, and I have in any case been meaning to fix the Mondeo and stick it in for an MOT, is it worth trying to refurb the caliper instead? It might not be easy to get the seized piston out, but if I'm not fussed about saving it I could try all sorts of brutal tricks. My mate has a cheap air compressor we could try, or I could drill through it and try twisting it with some bar...

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I'm guessing you've not got any hose clamps so I'd use some sockets over the ends of some long nose mole grips to clamp the hose.

 

Union from flexi to caliper shouldn't be too much hassle. Loosen it before you undo the caliper mounting bolts and then when you've undone the bolts spin the caliper off the flexi otherwise you'll possibly damage it.

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If you are desperate, you should be able to get the piston back in with pressure. Loosen the MC resevoir cap, too.

Got a pair of these?

 

http://wickes.scene7.com/is/image/travisperkins/largeNormal/Plumbing-Tools-Wickes-Water-Pump-Pliers-9-4in~T3274_500511_00?defaultImage=travisperkins/missing-product

 

As you are not stranded in the Gobi Desert, just change the caliper, though.

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Don't use force to push the piston in.......give the pedal a pump to push it out (then clamp the flexi) then clean everything and reassemble. refit piston with bleed nipple open. If it won't go in with just fingers then it is not right....you need to jiggle it to get it started in the seal. Piston does need to be is reasonable order though.

 

This is not budging it is repairing!..........I don't buy new until I know why/if the old one is buggered

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I have a pair of those pipe pliers, that was what I was using initially! I haven't done any deadlifting for a few years but I reckon my grip strength is probably still pretty good, and the piston wasn't going anywhere.

 

The bleed nipple looks completely knackered as well, it seems to have rusted in half, can't see how I'd get a bit of pipe on it! I think I'll order a refurb kit and start again with a nice clean piston, new seals and dustcap etc. etc.

 

Edit: and a new bleed nipple, obv.

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Don't use force to push the piston in.......give the pedal a pump to push it out (then clamp the flexi) then clean everything and reassemble. refit piston with bleed nipple open. If it won't go in with just fingers then it is not right....you need to jiggle it to get it started in the seal. Piston does need to be is reasonable order though.

 

This is not budging it is repairing!..........I don't buy new until I know why/if the old one is buggered

The choice is spend hours messing about in the cold trying to revive a failed part or half hour and £50 and its sorted properly. If you rebuild the caliper you'll want some new seals as well.

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I always use/used a g clamp to push the piston back in, that way you can be very careful about how much pressure you put on it to wind it back in. Works everytime for me and I've never damaged anything brake wise.

 

Pump the position out and clean off the rust/detritus, lube up,wind back in and all should be well.

 

If it's tight then slacken off the bleed nipple, although I've rarely had to do this, usually simply removing the brake cap for the reservoir works just fine.

 

Holler if you get stuck mush.

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Although I am all for making do and mending, I think that this piston is too far gone to save- it really is stuck fast, it's covered in patches of rust where the chrome has gone, and there are a few gouges in it from corrosion build up on the caliper by the looks of things. I tried gripping the end (past where the dust seal would sit) with my pair of pipe pliers and I couldn't even rotate it in the caliper, let alone move it in or out. For once, I'm going to try and do the job properly, apart from anything else I'm sure the binding brake has been robbing me of a few MPG, I've been struggling to get much more than 55 round town recently! ;)

 

Edit: This looks like what I want, right?

 

https://www.ebay.co.uk/itm/FRONT-Brake-Caliper-Seal-Piston-Repair-Kit-for-PEUGEOT-106-1991-2006-BRKP41/272790579233?fits=Model%3A106&hash=item3f8395e821:g:TtcAAOSwwmlZhFFS#vi-ilComp

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Indeed. I've spent time pissing about with calipers, and would much rather just fit a new one these days. If you feel some mad desire, you could always rebuild the old one to keep on the shelf, when there are no time pressures. As well as the piston, the sliders might be gubbed too.

 

If I'm changing a caliper, I don't bother with hose clamps. There's little system pressure as long as no-one touches the brake pedal. My technique is to crack off the hose at the caliper end, THEN remove the caliper, effectively unscrewing it from the pipe as you go. Then wind the new one on (which can be a bit fiddly, as calipers can be heavy). A little copper grease on the bleed nipple might help save you trauma in future.

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If the old piston was a bit sluggish then I'd probably peel back the gaiter, clean up as best as I could and then work it in and out with waterpump pliers and the brake pedal a few dozen times.

If you can't push it back with levers and swearing then it's too far gone.

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No, I can't push it back in.

 

I'm not under any time pressure now I've blown out the trip on Monday, I live in London and get around by bicycle, I very rarely drive anywhere for my own benefit, so everyone else will have to lump it while I rebuild the caliper :) . The sliders are fine, maybe a tiny bit of sticktion when you first try to move them but definitely not enough to jam the brake on- in any case the rebuild kit seems to come with new slider seals so I'll repack them with moly grease while I'm doing the rest of it :) .

 

The kits don't seem to come with new bleed nipples though, where should I acquire those from?

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I had a 106 with a sticky caliper many moons ago, tried to force the brake piston back in and ended up physically bending a massive record g clamp. Then I opened the bleed nipple and that seemed to help a lot it - the caliper piston would return by hand.

I did replace the whole lot after but clearly fluid would not flow properly and as we know it doesn’t compress.

In regards to bleed nipples these calipers look very similar to the ones used on the rears of most French hatches (clio 172, 106 gti, Saxo Vts, 205 gti maybe? ) might be worth hunting in that direction for some

 

 

Sent from my iPhone using Tapatalk

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I’ve also found those Irwin gripping sockets are excellent at getting rounded off bleed nipples out. Failing crack the flexi union and bleed from there.

Strictly get you home bodge measure these mind you!

 

 

Sent from my iPhone using Tapatalk

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Update. I put an order in with Bigg Red for a rebuild kit when they re-opened on the 3rd Jan, arrived the next day, which is pretty good service if you ask me!

 

Today I finally ran out of excuses not to attack the job. I'd taken the caliper off the car a few days ago, surprisingly the flexi came off quite easily. But I didn't get very far today. Before removing the caliper I'd pumped the piston out another centimetre or so, as far as I dared basically. But I still can't move it with my pipe pliers. So I thought I'd try removing the bleed screw to get any remaining fluid out before attacking it with a chisel, or something.

 

post-20573-0-65701700-1516627024_thumb.jpg

 

Oh. Been online to have a look at how to remove them, and welding a nut on seems to be favourite. I do actually have a welder...I just don't currently have any gas for it. Thinking about trying to drill it out and running a tap down the thread? What do we reckon? I've given it another squirt of plusgas in the meantime.

 

Edit: the bleed screw was full of rust, so the fluid obviously hasn't been changed for a while. So that's my Gunson Eezibleed and 5l of Dot4 purchase justified, then...

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Dunno, more than the rebuild kit I've already bought, though!

 

If I actually relied on having a working car I wouldn't engage in all this tight-fisted messing about, but I don't, so I regard it all as a learning experience- if I can get a stuck bleed screw out, then that stands me in good stead for when I need to get a broken bolt out of something that can't as easily be replaced!

 

Anyway, these get generally poor reviews, but they're only 4 quid, and ought to stand at least a chance of working on an already hollow bleed screw, so I'm going to try and grab a set later:

 

https://www.screwfix.com/p/screw-extractor-set-5-piece-set/1112v

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Update time.

 

I bought the screw extractor set from Screwfix and had a go with it.

 

post-20573-0-47426000-1518028101_thumb.jpg

 

Great. So then I had a go at drilling the lot out with a hand drill, as my mate has my cordless drills at the moment:

 

post-20573-0-95719900-1518028160_thumb.jpg

 

At that point I fucked the job off for a few days. Having acquired a Lidl cordless Dremel knock-off I then set about trying to grind it out with a selection of diamond grinder bits:

 

post-20573-0-91077500-1518028404_thumb.jpg

 

...which actually seemed to work surprisingly well. But however big a hole I managed to get into it, the extractor bits did very little. Eventually after about 2 hours of grinding, drilling, and running a tap up and down I had it all out, but the thread got a fair kicking in the process. It will take a new bleed nipple fairly securely:

 

post-20573-0-20335000-1518028563_thumb.jpg

 

...but when you put your finger on the hose hole and blow down it the air leaks out past the threads. I was initially pretty downhearted by that, but reading up on it it turns out that the seal is made by the bottom of the bleed nipple seating against the caliper, not by the threads...

 

 

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...so on to today- having a go at rebuilding the rest of the caliper. The piston was still stuck pretty fast but using a pair of pipe pliers and a lot of brute ignorance I got it spinning, and was able to shuffle it out bit by bit.

 

post-20573-0-64897000-1518028876_thumb.jpg

 

Popped the pretty shagged looking old seal out:

 

post-20573-0-24525200-1518028915_thumb.jpg

 

I then seat about cleaning as much crust as possible off the outside bore of the caliper and the groove the seal sits in using a little wire brush in the cordless mini drill. This would have been a lot easier had I removed the pad carrier, but I still don't have the 5-sided socket, and even if I had I very much doubt the bolts would have wanted to come out.

 

post-20573-0-63294600-1518029065_thumb.jpg

 

The brush tool did a pretty good job on the outside, less so on the seal groove. Anyway, I cleaned as much crud away as possible with kitchen towel and cotton buds afterwards.

 

I got bored of taking photos at this point but I decided to remove and re-grease the sliders and replace their seals even though it still moved freely. That may have been a bad idea as the ends of the slider pins were badly corroded, I should really have bought new ones, but the insides were OK and so I covered them in moly and shoved them back in with the barely fitting new seals.Then it was time to put the new seal and piston in- I used the supplied sachet of silicone grease for that:

 

post-20573-0-12577400-1518029375_thumb.jpg

 

It went in with a little more persuasion than I'd hoped, but fingers crossed that means the seal will be tight. Fitted the dust cover afterwards, hopefully it stays on as I assume all the pitting on the previous piston was as a result of it coming loose.

 

post-20573-0-44999700-1518029486_thumb.jpg

 

I have no idea what this o-ring is for, there were four in the kit, two per side:

 

post-20573-0-94295500-1518029539_thumb.jpg

 

...so I've put them back in the bag. Finally I popped to Euro Car Parts and Toolstation (both within walking distance of my house, there are some advantages to living in That London, albeit not many):

 

post-20573-0-79455700-1518029637_thumb.jpg

 

The little white round thing is a 22p roll of PTFE tape, which I am hoping will do the business on the shagged bleed nipple thread when I attempt to get it all back together tomorrow morning.

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I was hoping to finish the job this morning but time has slipped by quicker than planned, as usual. Application of PTFE tape to the bleed nipple made it airtight to the pressure capable of being generated by my pursed lips, so that was encouraging. I've managed to bolt the caliper (and new disc and pads) back onto the car. I shredded one of the slider seals in the process, though- guess I should have installed the pads afterwards rather than trying to force the slider pin right back, but that would have been a problem in itself, as the pad retaining shim thing was bastard tight to get in. I will keep an eye on it; I should really have replaced the pins anyway.

 

So hopefully I can bleed it up tomorrow morning and have a working car. Fingers crossed!

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