HP2 Caliper rebuild

[waveydavey]

Anybody know of a good guide to rebuilding the iron HP2 calipers fitted to the urS6? I've found one for the B5 alloy HP2s but they seem a bit different from the C4 ones.

Anybody know the size of the Torx (or similar) bolts that hold the two halfs of the caliper together?

Cheers

David

[Dybro]

Hello David
I have rebuild a set of iron HP2's 2 years ago. I just bought two seal-kits from Budweg Caliper. The torx-like bit is a XZN (aka triple square) bit. I don't remember what size but I think it is a XZN-M10
If you need new pistons then Budweg can deliver those too

The rebuild job itself is pretty straight forward. To make the inner dust-boots seal properly(crawl over the lip. don't know what it is called) can sometimes be tricky. But they should seal when the inner caliper part and the carrier is squeezed together.

The XZN bolts should be torqued to about 65 Nm or so (anyone knows??). I gave them some thread locker just in case....

I'm sorry that I can't give you a detailed guide but I hope this will do

[waveydavey]

Thanks Dybro

I'll get a XZN-M10 bit ordered and see what the calipers look like apart. K7ERG has sent me a link to replacement HP2 calipers for 58 UKP each exchange so I'll see if I need new pistons and decide whether to rebuild or get replacements.

Do the Budweg seal kits have the three bellows for the slider mechanism or just the piston seals and dust covers? I've heard you can't get the bellows for the B5 alloy HP2 and my iron ones definitely need new ones.

Cheers

David

[Dybro]

don't order that xzn m10 - when I get home tomorrow I will check what size is the correct one, just in case...

Budweg have ALL seals for the HP2 caliper - high pressure seals, piston dust covers, the bellows and the brass slide pin bushings. (P/N: 204324)



- According to Budweg the complete seal kit and the pistons for the C4 and the B5 is identical

pistons(one pair) is P/N: 234330

[Dybro]

Okay. I just checked what size xzn is needed.. it turned out that it is the 12 mm xzn

[waveydavey]

No worries Dybro, I've ordered a set that has the M10 and M12 xzn bits.

Cheers

David

[Petu]

Does anyone here know where to get the 2 middle slider pins? Have not found any part numbers only few pics from russian forums.

[UrS4boy]

Budweg have ALL seals for the HP2 caliper - high pressure seals, piston dust covers, the bellows and the brass slide pin bushings. (P/N: 204324)- According to Budweg the complete seal kit and the pistons for the C4 and the B5 is identical

I contacted Budweg via their website yesterday regarding rebuild kits for the HP2s on my 94 S4 V8 avant. So far, no response. Do they deal with the public or are they wholesale only?

[waveydavey]

I got my Budweg rebuild kits from Brake Parts International www.brakeparts.co.uk

Cheers

David

[UrS4boy]

I got my Budweg rebuild kits from Brake Parts International www.brakeparts.co.uk Cheers David

Thanks. I just tried to buy a BCK 4324 kit (2 kits actually) from Brake Parts International but they don't list Canada as a country they ship to. I've emailed them to ask for suggestions.

Turns out the BCK 4324 kit (presumably the same as the Bugweg 204324 kit) is also the UFO inside rotor caliper kit. Interesting.

[twoqu]

http://www.ebay.co.uk/itm/AUDI-S4-2-...25465#shpCntId

[UrS4boy]

http://www.ebay.co.uk/itm/AUDI-S4-2-...25465#shpCntId

Thanks Robin. Unfortunately, it introduces a new PN, BCK4324B, i.e. like BCK4324 but with a "B" at the end. Brakeparts.co.uk does not recognize BCK4324B in their system.

[Vorsprung durch Technik]

Really useful thread this. Would be nice if someone knows the answer to Petu "Does anyone know where to get the 2 middle slider pins" I guess you cannot say your have fully refurbed your calipers unless these slider pins have been replaced.

[UrS4boy]

Does anyone here know where to get the 2 middle slider pins? Have not found any part numbers only few pics from russian forums.

Typically, unless the slider pins are bent they can be cleaned with a very fine (say 600 grit) wet/dry sandpaper and then regreased. BTDT (but not on HP2s).

[UrS4boy]

Thanks Robin. Unfortunately, it introduces a new PN, BCK4324B, i.e. like BCK4324 but with a "B" at the end. Brakeparts.co.uk does not recognize BCK4324B in their system.

I emailed both the non-eBay and eBay versions of Brakeparts.co.uk last night. Here is a response from the eBay version:

"Dear decodave3,

Hi, thanks for contacting us.

BCK4324 / 204324 / BCK4324B are all the same thing, our part numbers are based on Budwegs number as we source all such components from them.

(BCK Brake Caliper Kit) the B on the end just tells us the vehicle the part is listed against as the kits often fit many vehicles.

Our current web site is not set up for non EU countries, however this is in hand and our new web site, which is due for release later this year, will apparently allow a much broader range of locations.

Ebay allows a much greater flexibility for shipping as we can tailor each item to our shipping needs and BCK4324B does have a shipping option for Canada.

I hope this helps

Kind regards Dave


Customer support
Brakeparts.co.uk
Tel:- 01706 662986
Mon-Fri: 9AM-5PM PST"