Xantia Activa failed MOT on rear brakes. IT PASSED!

[chrisjvm]

Hello Gents,

I fitted new front discs and pads to the Activa thanks to invaluable advice from XAC and RichardW.
But it failed on "little or no effort on rear brakes" the day before Good Friday.
I haven't had any time to sort it since apart from WD40 all over the calipers and driving it doing some 'emergency stops'
I took it for retest this morn on a wing and a prayer as brakes did seem a bit better ...
Anyway it failed again (unofficially) and I've got to take it back tomorrow at 4pm.
I've just done what KP suggested on an old post 'drop suspension on low setting,foot hard on brake,put suspension on high setting foot still on brake ... The rear stayed down until I took my foot off the brake ...I think this proves that the spheres aren't U.S.?
After that i put some heavy sandbags in the boot and this did seem to improve the braking effort as the ABS seemed to kick much more... When I braked heavily.
Is there anything else I can do/check before I take it back for the retest ...
Is there a way of finding out if the calipers are seized?
Discs and pads although not new, seemed ok.

Thanks in advance and apologies for the rambling post!

[RichardW]

Remove the pads, clean them up and grease them.
Bleed the brakes.

That should see it good enough for MOT - although if they are really not working then the discs may be in a poor state.

[chrisjvm]

Thanks for the prompt reply Richard!
Is there a dumb questions amnesty on this forum?
If not I'm going to go for it anyway!
How do I bleed the brakes,can I do it on my own?
And where do I grease the pads ?? (dumbest question!) Of the 3!

[xf1ref]

If I understand correctly you used WD40 on calipers? I don't think is a good idea because WD40 contains some oils. You should clean calipers, discs and pads with spray brake cleaner.
You also can bleed the back brakes, rise the car on maximum, put the jack under the car and remove the wheel and with engine running somebody have to stay with the foot on brake pedal. Unscrew the vent from the caliper a little bit until lhm start to flow...I usually use the hose from lhm tank plug to flow lhm in a bottle.

[RichardW]

Bleeding brakes on a Xantia is a piece of cake I would do this:

High suspension, jack up and support both sides, remove rear wheels.
Clean up round the bleed screws, and apply some penetrant - something better than WD-40! eg Plus gas
Remove the small 8mm through bolt that holds the pads (and cover and spring) in place - note how the spring is fitted
Remove the pads - you will probably find that the caliper is twisted and the pads are worn on an angle - let's ignore that for now, and don't mix the pads up. You may need to squeeze the pads back to get enough room to get them out.
Clean the backs and edges of the pads, and the caliper, so that they will slide in and out easily
Now apply a small amount of copper slip to the metal sides and back of the pads where they slide into the caliper
Refit the pads, bolt, spring and cover

Now, get a length of tube and a bowl. Slacken the bleed screw - carefully!! Use a 6 flat ring spanner, and give it a gentle shock with your hand. If it won't go, gently tap it on the top and try again, if it still won't go, then consider applying some heat to it, and then quenching it with plus gas. Eventually it will let go!
Retighten the bleed screw, start the engine, and wedge the brake pedal down with a length of wood against the seat.
Fit the pipe to the bleed screw, and crack it open 1/4 - 1/2 turn - LHM should start to flow out. On the first side, let a good amount (500ml or more) bleed out, retighten the bleed screw, then do the other side.

[Hell Razor5543]

^^^ What RichardW said^^^

However, I would add three things. First, be careful with those bleed nipples, as they apparently are now NFP (http://www.frenchcarforum.co.uk/forum/v ... 15#p407115" onclick="window.open(this.href);return false;). Second, I would also smear some copper grease on that thin calliper bolt, to help there, once you have re-fitted the pads, etc. Third, while you are bleeding the brakes see what colour the fluid is. If it is green it is still good. If it is yellowing then it is still good, but showing its' age. If it is brown get ready to replace it.

[RichardW]

Never had a problem with any of my BXs or Xantias passing on rear brake efficiency without any weight in the boot - when I've seen it tested they always managed lock up on the back Even the one where I got an advisory on the rear brake pipes, and then it burst about 3 months later - and the rear brakes were so seized I had to saw one of the pads in half to get it out!!

I forgot to add to the above - top up the LHM level when finished!

[Hell Razor5543]

When you get your LHM avoid Halfrauds. They are charging £12.99 for their own brand LHM+, whereas GSF are charging £6.24 for Morris LHM+. I checked the prices while adding this post.

[shauny0305]

Hi Chris, you mentioned "silly questions". Just check on you"re failure that the handbrake has passed, and they"re not testing that on the rear wheels,as that happened to me before.

[Hell Razor5543]

I have a simple attitude re. silly questions. Unless you are setting out to wind somebody up, there is no such thing as a silly question. If you have to ask it, it is because you don't know the answer (or you need to clarify something). I used to teach PC maintenance, and I used to start new groups with the comment "There is no such thing as silly questions, just silly mistakes. If you don't know, ask."

I had one MoT guy (who did pass my car of the time) why the handbrake was on the wrong wheels. Rather than try and explain, I demonstrated. Using the handbrake, I sent the car from service low to service high, and the nose position stayed where it was. We then chocked the rear wheels, released the handbrake, and dropped her back to service low. The nose then ended up forward of its original position. The MoT guy thanked me, saying he would try and remember this for future Citroens that he had to test.

[RichardW]

I think the front handbrake is more related to stopping erratic behaviour at the rear - especially on earlier sinking cars. If you jam the rear wheels, then you can confuse the height corrector, and it can lead to the car either jumping in the air, or falling flat on the floor, when you release the handbrake. Not behaviour likely to endear 'those complex French cars' to the unwary

[Hell Razor5543]

It could be we are both right. Certainly when I did that demo the nose moved forward by about an inch as the car dropped. Not good if you have parked very close to something fragile (like a window!).

[CitroJim]

I think the front handbrake is more related to stopping erratic behaviour at the rear - especially on earlier sinking cars. If you jam the rear wheels, then you can confuse the height corrector, and it can lead to the car either jumping in the air, or falling flat on the floor, when you release the handbrake. Not behaviour likely to endear 'those complex French cars' to the unwary

I would agree. From high to low the wheelbase changes by getting on for a couple of inches. It's a natural consequence of trailing arm rear suspension...

[Old-Guy]

Reverting to topic. Personally, I use an 'ordinary' hex (not bi-hex) ¼" drive 8mm socket on bleed nipples and I too noticed the other day that they are NFP. I've never had a problem with any of our Xantias failing on rear braking efficiency - and I stopped bothering to put weight in the back after forgetting to do so several times and still getting passes.

Despite her sitting outside unused for 10 months, I was pleased to see the Green Lady fly through the MoT last month without any problems - producing an impressive level squat on the brake test and almost perfect side-to-side symmetry. THough I have to admit that she did have a thorough rear brake overhaul about 18 months ago - calliper corrosion dealt with and new discs and pads.

Will be salvaging the rear callipers and discs from the VSX.

[chrisjvm]

Many Thanks to all of you that contributed advice to help me get my Activa through its MOT.
In the end I replaced the rear pads and bled the brakes and put a substantial amount of weight in the boot!

Now I've got to decide what to do with it.... Activa or T5 (280bhp) ? One of them has got to go ....
If I took fuel consumption in to consideration,they'd both go !!

The Activa's sublime handling and smoothness or the Volvos raw power and pipe and slippers image ! ?
Decisions decisions......