Xantia MK II - Low rear brakes efficiency
Moderator: RichardW
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- (Donor 2022)
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Re: Xantia MK II - Low rear brakes efficiency
So is there a way to test the rear brakes before MOT ?
Xantia 2.0 16V Automatic make year 2000 LHD
Citroen C4 THP Automatic make year 2009 LHD
Citroen C4 VTS 2.0 16V make year 2006 LHD
Citroen C4 THP Automatic make year 2009 LHD
Citroen C4 VTS 2.0 16V make year 2006 LHD
Re: Xantia MK II - Low rear brakes efficiency
Not really - not in a way that would give you an idea of pass/fail.
I usually just try a few hard stops from speed and judge how much the car lifts at the back. If the car lifts a lot at the back the rear brakes aren't working properly. If it only lifts slightly or doesn't lift at all they are usually working well.
When you brake the centre of mass of the car is thrown forward, this will try to compress the front suspension and extend the rear suspension, so if the rear brakes don't work this momentum will throw the rear suspension right up to the top limit stop. Also the torque from the front brakes will try to lift the rear suspension as well.
When the rear brakes work the torque from the brake clamping on the turning wheel will try to rotate the trailing suspension arm forwards, this will compress the rear suspension. So the rear brake torque works to counteract the natural rise of the rear suspension under braking. Ideally they equal each other in which case the car stays level under braking.
If the rear brakes are working well and the front brakes are not working properly you can even see the rear suspension duck under braking...
You will also see this effect when the car is on the brake tester machine - if it's only a single axle testing machine the rear suspension will squat down as the rear brakes are tested.
Simon
1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White
2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
1997 Xantia S1 3.0 V6 Auto Exclusive in Silex Grey
2016 Nissan Leaf Tekna 30kWh in White
2011 Peugeot Ion Full Electric in Silver
1977 G Special 1129cc LHD
1978 CX 2400
1997 Xantia S1 2.0i Auto VSX
1998 Xantia S2 3.0 V6 Auto Exclusive
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- (Donor 2022)
- Posts: 711
- Joined: 30 Nov 2010, 07:02
- Location: Israel
- My Cars: Xantia 2.0 16V Automatic make year 2000 LHD
Citroen C4 THP Automatic make year 2009 LHD
Citroen C4 VTS 2.0 16V make year 2006 LHD - x 8
Re: Xantia MK II - Low rear brakes efficiency
Hi
After changing the rear spheres and bleeding the brakes it passed the MOT today. Thank you all for your help
Zohar
After changing the rear spheres and bleeding the brakes it passed the MOT today. Thank you all for your help
Zohar
Xantia 2.0 16V Automatic make year 2000 LHD
Citroen C4 THP Automatic make year 2009 LHD
Citroen C4 VTS 2.0 16V make year 2006 LHD
Citroen C4 THP Automatic make year 2009 LHD
Citroen C4 VTS 2.0 16V make year 2006 LHD