[Brakes] Caliper Mounting Bolts Removal - Bosch or Lucas?

[cancunia]

Just had my MOT (passed) and got advisories on both front discs so need to replace them at some point. The tester  told me that the brakes are working fine so no great rush. I had a look at the calipers this afternoon and the first question that came up when checking for replacements pads & discs was if I have Lucas or Bosch brakes...
So far as I can tell from looking on service.citroen with my VIN is that they're Bosch, the Haynes manual shows shims on the Bosch caliper but not on the Lucas & mine has shims, so it's probably Bosch. Is there a way to be sure it's Bosch brakes that I have? 
I got the main part of the caliper off without too much bother but am stuck at the 2 mounting bolts that hold the caliper to the hub. They have large Torx heads, I have a Torx socket bit that fits but they're really tight and I'm worried about stripping the head in the bolt. Is there a proper / best way to get these things undone?

Thanks.

[V6BOY]

Should say what system on the caliper, the pad and discs should be both Bosch or both Lucas never really see them mismatched.Just make sure you have the torx bit fully home tap in with a hammer first.

[Civvic]

Just had my MOT (passed) and got advisories on both front discs so need to replace them at some point. The tester  told me that the brakes are working fine so no great rush. I had a look at the calipers this afternoon and the first question that came up when checking for replacements pads & discs was if I have Lucas or Bosch brakes...
So far as I can tell from looking on service.citroen with my VIN is that they're Bosch, the Haynes manual shows shims on the Bosch caliper but not on the Lucas & mine has shims, so it's probably Bosch. Is there a way to be sure it's Bosch brakes that I have? 
I got the main part of the caliper off without too much bother but am stuck at the 2 mounting bolts that hold the caliper to the hub. They have large Torx heads, I have a Torx socket bit that fits but they're really tight and I'm worried about stripping the head in the bolt. Is there a proper / best way to get these things undone?

Thanks.

penetrating oil perhaps?

[polar]

They are locktighted in but they should come undone with a breaker bar - give them a wack with the hammer before trying to undo them or if you can get some local heat in there and heat up the bolt head if really seized but i doubt you will need to with if you have a decent breaker bar.

[jj9]

What polar said.

The heads of the bolts are  T55, best clean them out with a sharp pointy thing to get any rust out of the groves then give them a good bash with a hammer, don't tickle them, hit them hard square on.

Then use a breaker bar and make sure to keep the torx bit held square on to the bolt.

Why they use torx head bolts and not just a standard 17mm bolt is beyond me, whoever came up with that idea wants a good arse kicking.

.

[ffrenchie]

Why they use torx head bolts and not just a standard 17mm bolt is beyond me, whoever came up with that idea wants a good arse kicking.

.

It's because they are easier to manipulate with a machine, not thinking that someone with hands has to take them apart in 10 years time. I did mine last year and penetrating oil would have made no difference as the bolts were Loctited. After the initial crack they came out no trouble but as before make sure the head is clean and the bit is knocked in well as the heads are not that deep. Daughter's Corsa used Allen bolts and one split when we did that, I had to weld an M10 bolt in it to get it out.

[cancunia]

Thanks for all the replies, I have more confidence now based on other's experiences. I'll try again with a bit more leverage & a bit of heat next time. I've cut down the Torx bit I was using to make it shorter (it was 75mm long) for better control and noticed that it's marked T55.

[cancunia]

The new discs & pads arrived yesterday so thought I'd better check they were the correct ones (Bosch), thankfully they were OK. There's nothing I can see on the old calipers or discs to say they're Bosch so in case anyone else has the same doubts, I think the following pointers may help:

Bosch pads are seated in the calipers using stainless steel clips at each side of the pad with no wear indicator wire, I think that the Lucas pads have a forked spring at the top and possibly a wear indicator wire.
According to Haynes, Lucas caliper pins need a spanner on the pin as well as the retaining bolt to undo them. The Bosch caliper pins are held in place by the caliper so only need a spanner or socket on the bolt head to release them.
When I put my VIN into service.citroen it was only one type of caliper / disc with no alternatives, although I did have to cross check the part number to find it was Bosch.

I finally managed to get the 2 Torx head bolts holding the caliper to the hub off with the aid of a chisel to start them turning, they were *tight*! I had a long enough bar on the Torx bit but am fairly sure it would have chewed the heads if I'd pulled much more. Fortunately, the mushroom shaped heads are broad enough that a chisel had an immediate effect. The bolts had no rust on them apart from a few mm right at the end of the thread so were not really rusted in, just really tight with thread lock. From the MOT history, the discs were replaced in 2008, they must have been done up with an impact driver set to 11, with added thread lock for good measure.

[timpascoe]

Thanks. All really helpful.