Xantia hop in brake pedal

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Eugene
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Joined: 28 Aug 2002, 02:17
Location: Ireland
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Xantia hop in brake pedal

Post by Eugene »

I have a 1994 Citroen Xantia with a slow hop in the brake pedal. The brakes come on and off slowly and can be felt in the pedal. The abs is working correctly, and anyway the hop is too slow. Front discs are not at fault as they are new and the hop is there when the car is stopped. It feels like a hydraulic problem. Anyone any ideas?
NiSk
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Joined: 24 Jan 2002, 20:11
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x 1

Post by NiSk »

Is the "hop" in the brake pedal connected to any clicking from the accumulator sphere regulator? Could be that your sphere's flat and you're feeling the pulses from the hyr. pump?
Otherwise it sounds like a fault in the ABS hydraulic regulator. Could be worthwhile checking earthing points and all ABS electrical connectors for bad contact.
//NiSk
Eugene
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Location: Ireland
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Post by Eugene »

Feels like the hop is from the pump. I've taken out the abs fuse,and no change. I bled the brakes from the wheels, no change. Should I relace the sphere, or is there somthing else I could try first?
Thanks for all the help and the quick reply
pwatson
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Joined: 22 Apr 2001, 03:02
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Post by pwatson »

Eugene,
This is a long shot but it worked for another poster on this board and it worked forme. We had this pulsing on a '93 TD even after new disks and a new pump. ABS also had no faults and spheres were in good condition. It was suggested by someone that the brake pedal was being fouled by the mat/insulation so I cut a bigger hole (with a Stanley knife) round where the doseur valve (brake master cylinder) is contacted by the brake pedal at the bulkhead. The pulsing was almost completely removed. However, compared with my BX and our newer Xantia the brakes were never as firm or consistent - seems to be a characteristic of certain years of Xantias. I have heard it said that it was a result of Citroen trying to make the brakes less sensitive for those not used to the power of Cit Brakes and they put a spring thing on the back of the pedal to make them "softer". I haven't inspected this - someone more expert than me might comment
PhilW
Phil
NiSk
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Joined: 24 Jan 2002, 20:11
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x 1

Post by NiSk »

1) If there is a regular clicking from the front accumulator assembly/hydraulic pump at a rate more often than every 5-10 seconds, then your accumulator is empty. It could be a good idea to change it anyway, they'er not very expensive.
2) the "silly spring" in the brake pedal arrangement, used to make the brakes feel more like a "normal" car's originated in the CX i believe, it's certainly fitted to all XM's but I didn't know it was found on the Xantia as well. There is a standard cure for this stupidity over here in Sweden - you just dismount the plastic connecting sleeve from the pedal to the brake distribution valve assembly (it's just pushed in place, in any case on the XM,) pull it apart, remove the spring and replace it with a nut that fits in the diamater of the sleeve. Replace the sleeve and Bob's your uncle.
Mind out the first time you try the bakes though! our you'll end up with a bunch of Ford Escorts in your rear! The modification also lowers the level of the brake pedal, so it gives a faster response time to braking.
The equivalent to an MOT tester who tried my brakes at the yearly test almost knocked his teeth out!
//NiSk
Eugene
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Joined: 28 Aug 2002, 02:17
Location: Ireland
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Post by Eugene »

Thanks to all for your advice. I replaced the rear spheres, because the rear was a bit hard. I replaced the brake sphere, bled the system, changed the fluid, cleaned the filters in the tank, and repaired two minor leaks. Then I pulled around at the pedals- seems pretty clear. Guess what, while much better, the stupid hop is still there? At least now its tolerable, until the next time I get a chance to play
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JohnW
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Joined: 09 Dec 2001, 03:40
Location: Western Australia
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Post by JohnW »

[quote]
2) the "silly spring" in the brake pedal arrangement, used to make the brakes feel more like a "normal" car's originated in the CX i believe, it's certainly fitted to all XM's but I didn't know it was found on the Xantia as well. There is a standard cure for this stupidity over here in Sweden - you just dismount the plastic connecting sleeve from the pedal to the brake distribution valve assembly (it's just pushed in place, in any case on the XM,) pull it apart, remove the spring and replace it with a nut that fits in the diamater of the sleeve.
//NiSk
From JohnW,
Thanks for this information. I finally took the plunge and wriggled under the pedals of my Xantia. I can report that my 1995 Xantia has the same plastic device with a spring acting on a plunger between the pedal and the brake valve. I pulled out the spring and replaced it with a nut drilled to 10.5 mm ID, and with the outside ground a bit so it fitted where the spring went. The nut was about6-10 mm thick (just small enough to be able to get the plastic plunger device back into place behind the brake pedal).
The result? Huge improvement in brake "feel", much like I remember a DS feeling many years ago. The pedal is now hard after a short initial movement. Lovely and feels safer too.
Regards from Western Australia - just so you are reminded that this forum spreads far and wide!!
Cheers
JohnW
dgs
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Post by dgs »

I would remove that spring but a im afraid i will do something wrong i get killed in a car crash. Where can i find procedure with some photos?
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