Xantia Brake fault

martin117 · Unread post by **martin117** » 28 Oct 2004, 16:01

Hi Guys, being a newbie am looking for help with my xantia 1.9 TF,
Had pre mot today but failed on "insufficient pressure vacuum to give assistance to brakes for at least two or more applications"
apparently on mots they have to check the brakes when the engine is not running. has anyone any ideas on this and/or will it be expensive to correct.
Cheers

Kowalski · Unread post by **Kowalski** » 28 Oct 2004, 16:38

It sounds like a new accumulator sphere required.
If you search on this forum, for "accumulator" you'll find out what it is, where it is, what it does and how to change it.

bxbodger · Unread post by **bxbodger** » 28 Oct 2004, 17:14

<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">insufficient pressure vacuum to give assistance to brakes for at least two or more applications<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
This sounds quite bizarre! I have never ever had the brakes MOT tested without the engine running-the reason being clear that there will be no servo assistance, or in the case of your Xantia, no hydraulic pressure.
If the brakes are so poor that they would fail the low efficiency required by the MOT test then you would certainly notice it on the road!!!
Does the mechanic who did the pretest understand that a Xantia does not actually have a vacuum servo- vacuum plays no part in the Citroen braking system!!
Personally I think they either simply don't understand how it works or are touting for work-was the pretest done at an MOT garage?

Unread post by **RichardW** » 28 Oct 2004, 17:24

Where's your garage - sounds like they do good MOT's[}:)]
From the tester's manual at www.motuk.co.uk
"For systems with a vacuum servo:
. If a vacuum servo is fitted, then with the engine off, totally deplete the stored vacuum by repeatedly applying the service brake. Fully apply the brake and hold at a constant pressure and whether the pedal can be felt to travel further when the engine is started.
For full power hydraulic systems:
3. With the engine switched off, repeatedly apply the service brake until the warning device operates. Check that at least two further applications of the brakes are available. In case of doubt the availability of two further applications can be established when testing the brakes on a Roller Brake Tester.
Reason for fail: b. insufficient reserve pressure to give at least two further applications of the brakes after the warning device has
operated."
Have seen my Xantia tested engine off, but they guy just stamped on the brakes about 5 times with the engine off.
Bit worrying that the garage don't know the Xantia has power brakes though!

bxbodger · Unread post by **bxbodger** » 28 Oct 2004, 17:25

Sorry, meant to put this link on- scroll down to the bit about servo assisted and powered brakes-the test must be done with the engine idling.
http://www.motuk.co.uk/manual_370.htm

Unread post by **RichardW** » 28 Oct 2004, 17:46

Yes, but the tests for pedal rubbers, pedal security, no creep / sponginess etc come BEFORE the rolling test, and include the engine off test I described above....

martin117 · Unread post by **martin117** » 28 Oct 2004, 20:03

Yes, the test was done at an mot station, they only do mots no work or anything so think they must be touting for business for other peopoe.
Took car to local dealer who says that as far as they knew the Xantia was exempt from this test, and that the engine should be running, that is why they put the handbrake on the front just in case the engine does stall when the car is moving, also took to ATS who tested brakes and guess what nothing wrong, have E-mailed motuk with findings to see if there is anything they can come up with, but have also picked up form VT17 just in case. Apparently from the Mot station they have to test the brakes with the engine off at least twice just to see if the car would stop. (of course it would but not if you keep pumping at it like i suspect they did.
Thanks for your help guys, if i get any more problems will definately look here first.