Poor brakes

[Dollywobbler]

The TXD does not stop as well as it should. It still stops well, but compared to The Green Tiger, it's a bit rubbish. It needs much more pedal pressure. No problems passing an MOT, but something isn't right. Anyone got any ideas what it might be?

Has a recon caliper on the offside front, not very old discs on front and brand new pads (which have now bedded in). Rear discs and pads aren't that old either. Doesn't pull to one side. Aside from what was necessary to fit the replacement caliper, I haven't bled each corner. Is that a sensible first step?

[mat_fenwick]

It can't do any harm (unless you snap a nipple off) but doubt that's causing your problem. My experience of air in the brake lines is that you get a delay before brakes are applied, more than a reduction in efficiency. Can you lock the wheels?

If it's down simply to higher pedal pressure needed for the same level of braking then it could be the spring between the pedal and doseur. Perhaps the Green Tiger's was removed, or stiffer? I've yet to establish which BXs were fitted with it, as it was something I asked about in the days of the Andyspares forum and was told it was only Xantias which had it! Which I now know not to be the case...

I'm pretty sure Timex doesn't have one, although the sharpness I noticed when driving then might have been partly down to the lack of ABS (smaller bore pipes). That's the reason I asked about ABS the other day - even without the spring in my red one doesn't seem to have the same response as a non ABS car.

[Dollywobbler]

Timex definitely had the better brake pedal. The difference between that and the Green Tiger was marked. I'll try and give it a bleed at some point. I optimistically soaked all of the bleed nipples with penetrating oil when I first got it and fill do so again.

[Tim Leech]

Mk1's brakes are much better than the Mk2, theres more travel. could be the LHM in the brake lines needs bleeding/changing.

[citronut]

if its all or nout ( no braking at first pressure on the pedal ) that is definitely air in the system,

didnt you say in another thread your accumulator sphere is flat, if so that can dump its gas into the system causing air in the brake circuit

i can see why or how MK1 and 2 brakes should differ in the slightest,


regards malcolm

,

[mat_fenwick]

You've probably seen a lot more BXs than I have, but do all the Mk1s you've worked on have the spring under the brake pedal too? I wonder whether it is just late Mk2s?

The larger diameter pipes on ABS cars may be a reason for a difference in feel, although not in this case. I don't think we yet know if they are poor performing brakes i.e. not capable of locking a wheel), or that more pedal pressure than normal is required to do so. (Which may mean they are poor performing, or maybe a design difference if Citroen toned down the feel of the pedal during the BX production run).

[Tim Leech]

Ive owned about 4 Mk1's now, all of which have had brakes that are pin sharp. The 16TRS and 19TZI are progressive but have more pedal travel.

[Dollywobbler]

Yup. There is definitely a massive difference between Mk1 and later Mk2 brakes.

Accumulator is an interesting theory. It's not a delay, a definite lack of stopping power unless you push the pedal really hard.

[Defender110]

Ive owned about 4 Mk1's now, all of which have had brakes that are pin sharp. The 16TRS and 19TZI are progressive but have more pedal travel.

So that is probably down to the spring in the brake pedal, MK1's apply direct pressure to the valve and those with the spring have to compress the spring before full direct pressure is applied to the valve.

[mat_fenwick]

Thinking about it, if your pump and accumulator are both past their best, system pressure overall is going to be lower. So perhaps not surprising braking performance is suffering. We can see what it's like on Friday and take it from there.

[citronut]

You've probably seen a lot more BXs than I have, but do all the Mk1s you've worked on have the spring under the brake pedal too? I wonder whether it is just late Mk2s?

i must have lived a sheltered life Mat as i don't remember seeing this spring on BX's you all talk about

XANTS all the time but even themn i havent felt the prob a lot of XANT owners report,

The larger diameter pipes on ABS cars may be a reason for a difference in feel, although not in this case. I don't think we yet know if they are poor performing brakes i.e. not capable of locking a wheel), or that more pedal pressure than normal is required to do so. (Which may mean they are poor performing, or maybe a design difference if Citroen toned down the feel of the pedal during the BX production run).

the ABS theory is a good one though

[mat_fenwick]

When I first asked about it I was told quite categorically that it was only Xantias which had it, although the 3 (late) BXs I've owned all had it. It's possible it was softer and hence more obvious on Xantias? It's beneath the plunger I've got my finger on it this picture:



To stop it compressing when I press the pedal I just put a couple of blobs of weld on it, as shown in this fuzzy photo.

[Defender110]

My TZD has the spring fitted.

[citronut]

obviously one of those senior moments again as i didn't remember that device till seeing the picy's

regards malcolm

[Geoffrey Gould]

Hi, 1991 april, mine had a spring and it gave a soft pedal to start with, got rid of that, If I remember there were 2 dosier ( I know cant spell.) brake valve types 1 being a 2 slide type and the other a 3 slide type.The 3 being a later one I think.
One thing that Does make a difference is the make of brake pads.
Chris's car TFB always had very sharp brakes, a stand on the nose job. Mine a couple of years younger was/is not so sharp.
ABS brakes always seemed to give the feeling of ' am I going to bite, OK I will think about it. Yeah OK.' Not bad just very different.
Geoff.