Technical Front Brake Caliper : Piston Dust Boot

[HughJampton]

In the course of doing the 4th year annual service, I've noted (through a gap in the caliper) that the lower (larger) piston seems to have a split in the dust boot. The caliper hasn't, to my knowledge, ever been removed, so the split is a bit of a mystery.

It was MOTed for the 4th year, and brake performance figures are entirely satisfactory (both braking values and "bind" values). Patently, I'd like to address the split dust boot, but as cost-effectively as possible.

On certain vehicles, it is entirely possible to replace the piston dust boot by carefully expressing the piston until the mounting groove is revealed, removing the existing boot and then mounting and pressing in a replacement boot. The piston is then retracted. I'm not at all sure, however, that this is viable with the Ducato (2018 with Brembo brakes).

Has anyone had first-hand knowledge of such a procedure. I'd rather not have to go through complete caliper removal and refurbishment unless it is absolutely required.

 

[The Panda Nut]

I dont know but on my Bravo it was not possible to do as the caliper was built from the dust cover back and then sealed with a plug, so some are and some are not. take care, my exuberence cost me a replacement caliper. Pistons on most Fiats require screwing in to retract them and its easiest with the corretc tools. One side was a righthand thread and one side a left hand thread so again take care as its possible to ruin the caliper if you go the wrong way. With the correct tool is immediately evident if you need left hand thred tool. Tools available on eBay c. £20

 

[HughJampton]

Thanks for that. I'm also trying to avoid a new caliper, given the current braking data, but non-replacement of the boot is likely going to cause issues down the line.

I don't think (from pictures and videos) the pistons are "screwed". I have a RH thread retractor to hand anyway from previous brake work on other vehicles. I don't really want to attempt a boot-only replacement myself unless I can find info that someone has done it. (I don't want a "brick" on the driveway). Ultimately, if I can't be convinced it's possible, I'll look for someone to remove it and do a piston/seal rebuild.

 

[HughJampton]

Just rounding this off.

Local Fiat "professional" dealer wanted £100+ simply to diagnose before suggesting any remedy (you don't get anywhere near a mechanic, just a desk-jockey). Not prepared to even look at the photo showing the obvious problem.

Called in a reasonably local small independent (who are pushing maintenance of motorhomes). I was pointed straight at the mechanic, who said he wouldn't attempt boot replacement, but suggested remove and send off for refurb (which would mean the vehicle being with the 7+ days) or slightly more expensive, fit an exchange refurb ( in a day with about an hour's work).

Subject to the exchange being a Brembo base as per the Fiat original we agreed that, and it is.

Replaced today at somewhat less than £250 all in.

No diagnosis fee, and a new Fiat part alone is £500ish (though less from Coastal Motorhomes). Given I've currently got a bad back which constrains my own efforts, I'm reasonably pleased (at least as much as I can be when spending money on such things)