Xantia rear brake caliper bolts-removal

[xmexclusive]

Hi Andrew

I do not think you are any better off cutting the heads off.
Attacking the remains of a bolt with a pair of stiltsons is far more likely to bend the bolt and so snap it off.
Jims advice of slightly tightening to break the corrosion seal first is the way to get started. The microcracks from which the bolt will snap are almost certainly already there. When you tighten you put the microcracks under compression so there is virtually no chance of breaking the bolt off. When you try and undo the bolt you put the microcracks under tension. Twist too hard or bend the bolt too far and it will most likely snap off in brittle fracture like a carrot.

John

[NewcastleFalcon]

I followed the "Jim" method probably with my own subtle variations and it worked for the remaining intact bolt on the caliper.

It did take some time, and at times I felt as if the bolt was going to inevitably snap. The key for me was resisting the temptation to give the wrench a bit more oomph, as the endless repetitions of applying just enough pressure undoing and tightening seemed to be making no progress. I did it with a long bar, and literally hundreds of repetitions of applying and releasing pressure in both directions on the bolt, together with my releasing agent which came in a yellow tin from the local agricultural engineers, and smelt considerably more oily than WD40

I still have the broken stud of the other bolt to deal with, there is about 1/4 inch sticking out. I've soaked it both sides in the penetrating oil and will give it a go with molegrips in the morning. The easiest method by far is to weld a nut onto the stud. I have no welding skills whatsoever but I know someone who has if the molegrips fail.

What tool does anyone use to get the disc retaining screw out? I had to resort to hammering on an undersized 5mm socket to get it out.

Thanks for all your posts-so far so good but its not quite finished yet.

Neil

[CitroJim]

Pleased my method worked on your last remaining one Neil.

Try a set of Irwin bolt grips to get the stub of the other one out. They're reverse-flute sockets and do work.

They look like this:

What tool does anyone use to get the disc retaining screw out? I had to resort to hammering on an undersized 5mm socket to get it out.

It's a 5.5mm socket you need. Use it in conjunction with an impact driver; the type Japanese motorcycle engineers use to get Philips screws in engine casings out.

[NewcastleFalcon]

The other caliper bolts were not susceptible to the gentle persuasion technique, and in spite of an incredible amount of patience on my part, they did the inevitable and snapped off.

Waiting for Les, and his oxy acetylene bottles to ride to the rescue

Neil

[NewcastleFalcon]

Xantia-Rear Caliper Bolts Removal Post-Mortem



Everything is back in place now, new bolts, discs, and pads. If you have to go through this trauma I would say:

have a really patient go at removing the bolts using the "Jim" method
In my case this worked for one out of 4.
If you are lucky enough to leave a stub poking out of the trailing arm which all three snaped bolts did for me, either do it yourself if you have the skills and equipment, or pay someone to weld a nut onto the each of the stubs.

I had no choice but to get Les to use his oxy acetylene kit as I started doing the job along the end of the local industrial estate and was miles away from the nearest usable electricity supply. I dont know much about welding but the job would have been so much easier if the electric welder could have been used-more pinpoint with the heat.

The remnants of the bolts were still pretty stubborn and it seemed best to attempt to move them before they cooled down too much.

I think I'll keep the three little welded stubs as a memento.

Thanks everyone for your help

All the best
Neil