Rear brake problem on my Nuevo

Hi, My 2003 Nuevo has just failed it MOT on rear brake efficiency. It just passed on handbrake efficiency. All pads are new and have been cleaned. The slave pistons look OK. I am just about going to replace the brake master cylinder. Has anybody had a similar problem

It's not unusual if pads are brand new, they need to be bedded in. How many miles since they were put in?

Paulmold wrote:It's not unusual if pads are brand new, they need to be bedded in. How many miles since they were put in?

They have done about 300 miles

As Paulmold says - the more "ridged" due to wear the discs are the bigger the effect. My first drive after a pad change on my old 60's car was a memorable one (because I thought the brakes had failed!). If that's the cause, you should be able to see by taking the pads out and looking at them, as only the ridges will be visible as wear marks on the pads.

[Edit: I would have thought they would have bedded in within 300 miles, but it depends how much rear braking bias the van has - prior to ABS they tended to have much less effect than the front and would bed in slowly. Post ABS they tend to be more balanced.]

Being rear brakes they don't get used much unless under hard braking. You need to do some hard braking to bed them in.

Not sure about the 2003 Nuevo , check to see if there is a load sensitive pressure limiting valve underneath. Is this fails or sticks it may see the rear of the vehicle being light and limit the pressure to the back brakes to stop lock up when the commercial vehicle they are derived from are running unloaded.
.Can be as simple as a bracket and spring arrangement so easy to check externally.

Paulmold wrote:Being rear brakes they don't get used much unless under hard braking. You need to do some hard braking to bed them in.

Thanks for the advise, I will do some hard braking tomorrow.

kaspian wrote:Not sure about the 2003 Nuevo , check to see if there is a load sensitive pressure limiting valve underneath. Is this fails or sticks it may see the rear of the vehicle being light and limit the pressure to the back brakes to stop lock up when the commercial vehicle they are derived from are running unloaded.
.Can be as simple as a bracket and spring arrangement so easy to check externally.

Thanks for the advise I will check for a LSPLV tomorrow, I can now understand why they fit them

300 miles is plenty to bed in new pads.

Very unlikely to be a master cylinder problem.

Up to 2002 a rear brake balance valve was used and they do fail ! 
https://coastalmotorhomes.co.uk/citroen-relay-fiat-ducato-peugeot-boxer-brake-compensator-load-valve.html


What condition are the discs in, often the inner face of a disc is badly corroded even when the outer face looks ok.

Calipers are prone to sticking pistons especially on vehicles that stand still for long periods, any decent garage should be able to quickly determine the reason for poor efficiency of the rear brakes, if both calipers are playing up it may be time for a pair of exchange calipers, 15 years is perhaps the service life even if the mileage is comparatively low.

spanner wrote:300 miles is plenty to bed in new pads.

Very unlikely to be a master cylinder problem.

Up to 2002 a rear brake balance valve was used and they do fail ! 
https://coastalmotorhomes.co.uk/citroen-relay-fiat-ducato-peugeot-boxer-brake-compensator-load-valve.html


What condition are the discs in, often the inner face of a disc is badly corroded even when the outer face looks ok.

Calipers are prone to sticking pistons especially on vehicles that stand still for long periods, any decent garage should be able to quickly determine the reason for poor efficiency of the rear brakes, if both calipers are playing up it may be time for a pair of exchange calipers, 15 years is perhaps the service life even if the mileage is comparatively low.

Thanks for advise, will start to work through all the options again tomorrow

spanner wrote:
What condition are the discs in, often the inner face of a disc is badly corroded even when the outer face looks ok.

My van is 2004 and the rear brakes are drums/shoes. I've had problems with the rear brake efficiency, I took them apart and the problem was in the handbrake auto adjust mechanism. I bought and fitted a pair of new units from Peugeot for £100. No problems since, and as a bonus the handbrake is also more efficient.
Al.

I'd forgotten that Nuevos of that age have drum brakes so may be nothing to do with bedding in. OP says it passed on handbrake though so I'm guessing at brake cylinders.

hedgehog wrote:Hi, My 2003 Nuevo has just failed it MOT on rear brake efficiency. It just passed on handbrake efficiency. All pads are new and have been cleaned.

All pads are new ??????    Does your van have drum or disc brakes on the rear ? 

If it has discs then the handbrake mechanism is inside the disc and has a separate set of handbrake shoes.

If you don’t have discs on the rear then you have drum brakes which have brake shoes operated by wheel cylinders.

“Just passed on handbrake efficiency “ isn’t really good enough and won’t get any better either.

We had the same problem for the first time this year with the sensitive pressure loading valve. it was seized/stuck, they just freed it up for it to pass the mot, they did say it happens from time to time on motorhomes as the loading is a bit variable.

bikeralw wrote:
My van is 2004 and the rear brakes are drums/shoes. I've had problems with the rear brake efficiency, I took them apart and the problem was in the handbrake auto adjust mechanism. I bought and fitted a pair of new units from Peugeot for £100. No problems since, and as a bonus the handbrake is also more efficient.
Al.

Thanks, when I checked the shoes I also checked the handbrake adjust mechanism, it seemed OK but worth another try before I move to master cylinder. and sensitive pressure loading valve. Got my mate coming over on Thursday to assist in sorting.

My 2001 Hymer failed its MOT because of a dodgy brake distribution linkage at one stage.  It was not an expensive replacement.  As I recall it is fitted at the rear near to where the handbrake cable equalising pulley lives.

hedgehog wrote:Hi, My 2003 Nuevo has just failed it MOT on rear brake efficiency. It just passed on handbrake efficiency. All pads are new and have been cleaned. The slave pistons look OK. I am just about going to replace the brake master cylinder. Has anybody had a similar problem

Thanks to everybody for your inputs. Just a short note to update you how the problem has been resolved and my van passed its MOT. My friend Alex checked out al the mechanical parts and concluded it must be a hydraulic problem. Not slave cylinders as they were retracting OK. Conclusion Load compensator valve or Brake master cylinder. He replaced the Brake master cylinder which sorted the problem showing good results for brake efficiency at the MOT. The conclusion a seal in the master cylinder was the problem