BXProject

[Vanny]

Managed to pick up some Xantia ACTIVA calipers today, £50 for a set including bolts, discs, pads and removal from donor car. Well this evening i thought i'd go do some more clearing of the garage, which turned very rapidly into having a trial run of fitting the discs to a spare hub i had flatoing around.

these are the calipers i have;





I believe they are Activa MK2? Still i think they are 283mm. Need a damn good clean and have a bit of corrosion, but then who cares? I might clean them and paint them, but probably not!

So fitting, i learned from Simrans mistake? and made sure i obtained the bolts with the calipers. T55 headed but the same thread as those on the BX regular. The holes in my hub where very corroded, i havent a suitable tap to hand so padded out the bolt with a washer to take up the slack, you can see it here;



The Disc is held on with a couple of wheel bolts, again i needed spacers to hold the damn thing flat (usually there would be a wheel to make up the gap).

So oh wise people am i right in my fitting solution or have i missed something??

[Philhod]

Not sure what you are asking really, but there should be no need for shims or ersatz washers usw. Once everything is cleaned and dismantled, re tap al holes (I have a lot if your stuck) use wet and dry under a flat piece of wood for bringing m/c'nd surfaces flat. When it goes back together there should be no need of bodges. The vented discs have some wear so should be checked for run out, using a DTI, when fitted to a different hub.
Check the seals on the handbrake auto adjust system, the grease inside will be sloppy if they are, or have been leaking.

[Vanny]

Excuse me sir, but erm, what?

Why are no shims needed? And why is shimming bodging? Perhaps you missed that these are going onto a BX, IE Xanty calipers, BX hub, hence alignment isn't perfect and thus lots of tinkering is needed!

Discs will be replaced before use on the car. Though i appreciate your point about run out, i would never in a million years have thought of that, even though its so bloody obvious. I also bont have a dti


Auto adjust seals where okay, until i tore one trying to cheat.

[Philhod]

Well you were using a washer coz you had no tap, if you had a tap you wouldn't need a washer.
If you need shims it's usually coz the part you are fitting doesn' in fact fit and there is a gap, or there are inconsistencies in the 2 mating surfaces.
If the former, the gap should be measured and a suitable piece of shim steel procured, to cover as much of the surface as possible.
If the latter, careful metal removal...fine grinder, file, wet/dry is the way to go but remember, this requires a fair degree of hand skill.

I have a mag base DTI.

[docchevron132]

He needs the shims because the caliper has to be mounted slightly offset, not direct to the hub carrier as it wont line up with the disc since the Xanty hub carrier is different.

Again though, I really dont see the need for bigger brakes on a BX, the standard set up is just fine, if you're racing the thing, then EBC pads. Still fine....

[Vanny]

nargh, not fine, try racing one, the standard brakes with EBC red or green just aret man enough after a short while

[docchevron132]

I've never had brake fade...

[Bx Bandit]

Quick thought....will they fit behind std 14" rims?

[mat_the_cat]

I get fade within 20 minutes of hard driving on my way home - admittedly genuine pads are better than most of the aftermarket stuff I have tried. Might have to try the EBC ones...I presume the trade off is price and a shorter life? (I get ~7k at the moment)

[docchevron132]

You have vented discs?

I've been using EBC pads for about 5 years or so now, I get about 15K miles from them, and they dont plaster everything in shitty brake dust.
Ok, I dont drive like a nutter most of the time, but I've had the valver round a track a few times, and never had brake fade at all, ever.
I did have brake fade in the diesel once, but it had solid discs at the time...

[Vanny]

EBC pads are damn good, especially when i get sufficient discount to make them about the same cost as regular bendix pads. No the calipers wont fit under the 14" rims (and one of the reasons they wont be going straight on the car) but i'm not worried as they will fit under the 17" alloys, and this is not a daily driver.

One of the beauties of the BX on track is just how late you can brake, and usually out brake what ever is holding you up. I've had brake fade a fair few times on the racer, and that was with EBC greens and vented rotors, but most importantly not on road rubber or skinny little 14" standard rims. Anyways, point is that if you go hard at it the BX brakes will fade, they are no impervious, and the calipers them selves don work any differently from regular calipers. The LHM will bubble and the discs will get too hot.


Only real problem it looks like i might have is that these calipers seem to be unique and no one does racing pads or rotors for them

[mat_the_cat]

Yep, vented discs and calipers from a standard valver. I wonder whether the sort of driving I'm doing is more hard on the brakes than a typical track day (never having done one), and it is over a hilly area, with lots of hard braking from 60 (ish!) down to 30mph for the right angled bends. If I take it easy it's OK, but I do enjoy a good B road blast (the B4391 between Bala and Llan Ffestiniog to be precise.)
The BX wheels are fairly solid, so there is probably little in the way of cooling air passing through them.

[Vanny]

The BX alloys in theory are shaped to suck air in, if your going to believe the Citroen propaganda. Steels aint so wonderful, but air cooling still wont resolve the problem.

Sounds like the worst sort of driving for the brakes, i know the sort of roads you mean where you can open up the throttle before crashing on the brakes to make the turn (try the route upto the top of movama(sp), starting from the BACK!), the weight shifting and very on off on off braking will induce more heat than a track day, but in a similar way. Typically tracks flow so you get a bit of time on full chat (cooling the brakes) before breaking back down. The track i've done the most driving on is the old Anglesey Circuit, short, tight and very intricate, so not your average motor racing track. Aintree on the flip side is a fairly open circuit, mostly simple curves to get round so less braking and lots of cooling.

[docchevron132]

Just drive like a grandad.. no problem..

[Bx Bandit]

/\ The last time I got brake fade was in the Morris Minor with 7" drums! I'm all grandad in the TD! Anyway, your calipers 'may' just 'may' be the dsame as some of the other Xantia models Vanny? I'm not certain but I mention it because I had to buy a replacement caliper for my 2.1 TD Xanty but got supplied the wrong ones. The difference being the larger sliding bushes on mine which was only on the 2.1 TD and some of the more sporty petrols. Where that leaves you with better discs/pads I don't know but it may be another avenue to search along..................

[Vanny]

These calipers are unique to the Activa. Might be fitted to other pugs but nothing else in the citroen range, backed up by looking through the pads catalogue, not to mention the discs catalogue. I have the tech data for all pads and disc sizes fitted to the Xantia models. I'm not able to look at c5/6 as i believe the mounting points are different (further apart) so would require some serious hub surgery.

The 2.1TD and 2litre turbo models seem to have the same pads though, infact so does the Mk1 Xantia, but the Mk2 are different.

I can usually induce brake fade in the transit, its more about load not just how fast one reduces speed. I'm talking fade, reduction in capacity/ability not a total fail, sponge on metal type failure.

[smiffy]

I've never had brake fade...

I fucking have, virtually every sunday night on the way home from the farm, in the usual race along the ring road...this was how I lost the engine on my 16v

My CX turbo suffers dreadfully from brake fade on this road, and that's with genuine Valeo pads all round.

[docchevron132]

No, thats not quite right is it J!
You lost the engine because it had no oil in it and you went racing round bends....
I dont think the brakes had much to do with that to be honest!

[Way2go]

I thought Smiffy meant he lost his engine by crashing into something by virtue of brake fade. Now I can't see how he ties the two together.

[smiffy]

I thought Smiffy meant he lost his engine by crashing into something by virtue of brake fade. Now I can't see how he ties the two together.

Ok, I'll try to explain. The A4174 is a ring road around the east of Bristol, that I travel on between the M32, and where I live in Kingswwod. It has numerous sections of short duel carriageway, with frequent roundabouts. In the times when the CX turbo was on the road, or when I first had the BX16v, I'd be having err, umm, (spirited drives with the local youth in pretend fast cars) Fuck it, ok, street racing!

Brake fade got so bad, there was no braking left by the time I got to either end of the road!

Now, the losing the engine bit, was because I allowed the engine oil level to drop to the min level on the stick, and I didn't know that when doing sharp turns while still carrying high engine rpm (on one of them there roundabouts) the engine ran dry!