Hi, Tried doing a rear pad and disc change on my mk3 gti, and discovered a torn dust seal boot. Do you have to remove the piston from the caliper to replace it? Not done a caliper refurb before, the piston winds in and out ok, so if i dont have to take it out id rather not! Cheers for any help
I'm afraid so yes, the lip of it sits behind where the piston is so you cant fit it with the pison in the caliper., VAG sell you a kit with the caliper serals and dust boots, plus a sachet of special grease. you pour the grease into a tub and submerge the seals in it for a couple hours before hand. You'll want a proper wind out tool, will make the job easier, clicky To refit the piston and boot, what you do is put the new seal in first, then fit the boot onto the back of the piston so the lip for the caliper is sticking out the bottom. then you need to locate the lip into the caliper carefully, then pus hthe piston into the caliper till it hits the threaded bit. Then carefully wind it in, as you do this gradually slide the boot up the piston till it eventually pops back into the lip on the top of the piston, then you can wind it all the way back in. then dry fit it to the carrier and wind the piston out till the play is mostly taken up, and bolt it down with new slider bolts. edit: obviously you'll want to clean the piston thoroughly and check for pitting & corrosion, and also clean out the dust seal lip so the new seal will fit into it nicely.
Rubjonny. I just discovers a split boot on my rear caliper so may well be intouch soon! Anyone got part numbers for the repair kit?
8E0 698 470 B - front/rear calliper slider repair kit - 9.66+VAT x4 (1 per calliper) contains: 2x boots grease 2x calliper bolts *** 8D0 698 671 - rear calliper cylinder seals - 12.28+VAT x1 (1 kit contains enough for 2 callipers) *** N 019 912 3 - rear carrier bolt x4
Thanks rubjonny! When you say from VAG do you mean the company VAG or was it a reference to dealers? Also, can you confirm a couple of my questions below please and do you have any part numbers for front caliper seals to complete the thread?
be prepared for a very fiddly job, i did all my calipers but the seals take a good 3 or 4 goes to get seated properly, make sure everythings mega clean so bits of grit etc cant damage the bores and pistons. it takes a fiar bit of force to get them in right but at the same time be careful you dont snag the seal and damage it, and everything ends up all slippery cos of the lube you have to use (ooo errr ) loads cheaper than refurbed calipers tho if you have the patience!
VAG = volkswagen audi group, so yeah your local dealer! x2 kits yeah, i copied it from a txt file i saved which was coverign all 4 corners. slider boots are the rubber bellows over the pins, and the caliper kit contains both the big dust boot plus the internal piston seal as an addition to the above, dont even bother to try it without a windback tool like this one
Thanks. I have a wind back tool so no worries there. Have you got the part number for the front caliper kit? I want to get these ordered tomorrow. Cheers
431 698 471 B - front calliper cylinder seals - 8.16+VAT x2 (1 kit contains enough for 1 calliper) N 907 085 04 - front carrier bolt x4
From speaking to TPS all prices quoted seem to have gone up a touch and for one of the part numbers the mk3 golf was not listed. Either way I think I have everything I need ordered now. Will post updated prices etc when I have them to hand.
yeah the prices are quite old, plus vat has gone up. i know in etka some of the sections list an older part number, but when you click on it the new number is shown. also the front piston seal is only for 256/280mm brakes, forgot to mention that. if you have 288s the number is different
Right, new seals, boots, bolts etc have arrived. I need to get stripping my old front and rear calipers so... How do I get the pistons out? Some are fully retracted, some mid-way and some fully out. How far can the rears be stripped easily? I'm going to be painting these so want to get them as bare as possible. Some pointers on all the tasks in hand would be greatfully received!
for the rears, just unwind em till the pistons fall out. for the fronts i fit a bleed nipple into the brake flexi hole and put a foot pump on it. couple pumps and piston will pop out. put it in a bucket tho as fluid will go everywhere pistons out is as far as id go on the calipers, you can take the bhandbrake lever off too if you plan to clean up and paint. stripping the handbrake mech is tricky as it requires you remove a circlip which is burried right inside there. really tough to get pliers with a long nose to get at it for the sliders, clean the pins and the holes till completly spotless. then inspect holes + pins for pitting and grooves. make sure pins slide in and out smoothly. also rears and maybe fronts have different pins in each hole, so dont mix them up! once cleaned and checked, give each pin a good coat of grease and pop them in the holes. wiggle and push in and out the hoes to make sure pin and hole get a nice even coat. pop boot on then job done! give em a few taps to make sure they go fully in and come out again smoothly. with the rear seals you'll get a sachet of grease, soak the seals in it for at least an hour before you rebuild. front seals soak in brake fluid for an hour or so, or use the rear brake stuff. clean out the caliper and buff up the pistons, make sure no heavy scoring or pitting on the shaft. fit the seal to the caliper, then fit the boot on the back end of the piston. you then have to wiggle it into the lip whilst pushing the piston in, as you go drag the boot up the piston till it clicks into the lip, then fully push in the pistons. for the rear, fit to carriers with the old caliper bolts, then adjust the piston till there is only a little play. the reason you do this is when fully wond in no fluid can come through! found that one out the hard way. once happy with the clearance bolt it on with the new bolts.
Sweet, Cheers mate. I've been giving them the ol' electrolosys method all week and have cleaned up really well. Will strip and paint tonight and rebuild Saturday time permitting (Need to change CPS AGAIN + oil + filter ). Will take some pics along the way if I have time for others future reference. I've got some nice new braided hoses to go on as well and fresh fluid. I'll be mightily unhappy if there isn't a noticeable improvement in break feel and a reduction in noise.
Hi guys, I need to service one rear os calliper on my mk4 - will these part numbers be the same for me?? and is that everything I need?
