Lackluster brake performance on my 4-ton motorhome (1 Viewer)

[roadwarrior]

i have got a 4 ton mercedes sprinter based winchcombe, it has got new disks and pads all round but i have to stand on them if there is a sudden stopping situation, they are bedded in as i have just returned from the pyranees, but they are still lackluster and dont inspire confidence - your thoughts ? they take a couple of seconds to bite and are fine in normal circumstances but.. as they are all round new discs im surprised they are not better.

 

[roadwarrior]

Is it manual or auto gear box?

7 speed auto

 

[roadwarrior]

Or they were fitted badly and got contaminated?

immediately i bought it last year with dealer fitted new front disks and pads ( makes uknown) it went to france and did 3000, so my guess would be no, while away the braked bedded in, but feel lacklustre, my feeling is as it has just been upgraded to 4250k i t would be nice to have some decent brakes

 

[roadwarrior]

I also have a 3.9t Mercedes Sprinter based motorhome and the brakes felt spongy when I purchased it. After a couple of months I noticed that there was a Commercial Mercedes dealership that serviced and repaired dozens of DPD Sprinter vans so thinking they would surely know if there is any problem booked it in. After tests and getting it on the rolling road I was informed that the spongy brakes were an anomaly to this model and they were working to the standard.
Following a MOT advisory a year later stating that the brake discs were now getting too thin and near to being out of spec I had the discs and pads renewed all round (at non Mercedes garage) and also hoping that this would make the braking much sharper. It did improve the pedal having less travel but brakes were still having that spongy feel but did pull up better. I guess I need to speak to a DPD driver to see what they think !

in all honesty i would be quite happy with spongy brakes if they stopped the van, and yes its seems sprinters have spongy brakes.

 

[DJT]

7 speed auto

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[ChrisL]

Not sure this is relevant but I have 6 tonne motorhome based on a 2004 Sprinter, it had new discs, pads and ABS rings fitted all round when I bought it three years ago, but the brakes have never been particularly great and require a fair bit of pressure to stop in an emergency, I haven't shunted anything so far but they are not super confidence inspiring and I always leave plenty of distance between me and the vehicle ahead. It passes the MOT okay though.

 

[Carpmart]

Not sure this is relevant but I have 6 tonne motorhome based on a 2004 Sprinter, it had new discs, pads and ABS rings fitted all round when I bought it three years ago, but the brakes have never been particularly great and require a fair bit of pressure to stop in an emergency, I haven't shunted anything so far but they are not super confidence inspiring and I always leave plenty of distance between me and the vehicle ahead. It passes the MOT okay though.

I’ve the same feeling in my 7.3T Motorhome. The brakes work perfectly fine but just don’t fill me with 100% confidence. I think braking benchmarks in the cars we drive everyday have just changed our perception…

 

[pelican]

Please share how air gets into the system winding the calliper pistons back.

I’m intrigued.

Probably more to do with fluid nearest caliper receiving high temperatures.

 

[Guigsy]

immediately i bought it last year with dealer fitted new front disks and pads ( makes uknown) it went to france and did 3000, so my guess would be no, while away the braked bedded in, but feel lacklustre, my feeling is as it has just been upgraded to 4250k i t would be nice to have some decent brakes

I don't think they maxi brakes offer any more brake force or feel. The difference is they need to dissipate more energy for the higher weight, so they have more thermal mass and cooling area. But only to reduce overheating. Bigger discs don't really help you brake better... Except in situations where the brakes are repeated loaded like going downhill... or racing. It shouldn't make much difference just for slowing down at a junction or stopping for lights because the temperature increase is small even on smaller brakes.

 

[roadwarrior]

Not sure this is relevant but I have 6 tonne motorhome based on a 2004 Sprinter, it had new discs, pads and ABS rings fitted all round when I bought it three years ago, but the brakes have never been particularly great and require a fair bit of pressure to stop in an emergency, I haven't shunted anything so far but they are not super confidence inspiring and I always leave plenty of distance between me and the vehicle ahead. It passes the MOT okay though.

thats my fear too - plenty of advance driving but no room whatsoever for emergencies

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[roadwarrior]

so, what vehicle has larger disks that wourld fit or maybe 6 pot calipers ?

 

[L' Hobo]

so, what vehicle has larger disks that wourld fit or maybe 6 pot calipers ?

Surely,if it passes MOT standards (and perhaps you might try a different station for a second opinion) without advisories, It should be okay?

What a lot of people don't realise is, there are many, many different pads and discs out there.
On my VW, I have a product called Black Diamond that I had fitted 5 years ago. The discs are harder than most and the pads are, and this is the important part, compatible to the discs.

IMO, there is nothing worse than not trusting ones brakes in an emergency, so good luck with your quest!

 

[Platelet]

I would take it to your local MOT garage and ask them to put it on the rolling brake tester and see what the results are?

 

[roadwarrior]

I would take it to your local MOT garage and ask them to put it on the rolling brake tester and see what the results are?

my feeling is EITHER lacklustre front pads OR the brake balance valve , either way it goes in for an mot friday 12th july with my freindly mot man who i have asked to give the brakes particular attention, it pulls up straight so will pass the mot ok but i have explained my concerns and feel sure he will have a good look for me, and the following friday it goes to mertrux for an engine and gearbox oil change for an eye watering 800 quid, but considering a sprinter engine takes 13.5 litres of oil its acceptable perhaps. its goes to europe for 9 weeks after that so i want it right

Of course it could be anything, upto and including a leaking hose.

 

[roadwarrior]

a quick inspection shows very nearly NO brake disk whatsoever - i cant help but feel the pads are just too hard

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[Guigsy]

a quick inspection shows very nearly NO brake disk whatsoever - i cant help but feel the pads are just too hard

Pads should always wear quicker than discs.

 

[vintageb3]

I’d try another make of pad.

 

[Garveypeter]

i have got a 4 ton mercedes sprinter based winchcombe, it has got new disks and pads all round but i have to stand on them if there is a sudden stopping situation, they are bedded in as i have just returned from the pyranees, but they are still lackluster and dont inspire confidence - your thoughts ? they take a couple of seconds to bite and are fine in normal circumstances but.. as they are all round new discs im surprised they are not better.

All things being equal, brakes bled and system functioning correctly, there are major differences in the braking efficiency due to two factors, pads and discs.
I’ve fitted many brake and disc pad sets and I’ve seen it over and over, new is not better as all pads and discs are not equal.
The likes of Mintex and Blueprint pads are average at best. The likes of Ferodo or Moog are OEM pad suppliers and the difference in stopping power can be dramatic.
Cheap brake discs don’t have the correct balance between wear and durability.

 

[Rimswell Wanderer]

i have got a 4 ton mercedes sprinter based winchcombe, it has got new disks and pads all round but i have to stand on them if there is a sudden stopping situation, they are bedded in as i have just returned from the pyranees, but they are still lackluster and dont inspire confidence - your thoughts ? they take a couple of seconds to bite and are fine in normal circumstances but.. as they are all round new discs im surprised they are not better.

This is a long shot but brake fluid is hydroscopic and absorbs moisture as in water usually recommended to be changed every two years and can affect braking properties so maybe change the brake fluid or have it professionally changed.

 

[roadwarrior]

Ok so, pads it is, now I fitted brembo disks and pads to my Passat a couple of months ago and I would say it's firm but reassuring. But for my MH I don't want firm. I already have firm but no bite and as already stated I have almost no brake dust, and I really want soft high cold bite pads and to hell with lots of brake dust, I can always clean it off. But I don't want to find myself in trouble next month IN the Alps. I'm thinking jurid - any thoughts ? This is a problem for many of us motorhomers so a definitive answer for us all would be helpful. Most pad makers want pads to last as long as possible but we don't, 30-60k is a lifetime to us, I would be very happy to have pads wearing out at 15k but stopped me with ease. What say you guys ?

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[Silver-Fox]

Probably more to do with fluid nearest caliper receiving high temperatures.

That doesn’t explain how winding back a calliper air can enter the system

 

[Silver-Fox]

a quick inspection shows very nearly NO brake disk whatsoever - i cant help but feel the pads are just too hard

Just one side or both sides?

Assuming we are talking the front ones?

 

[Silver-Fox]

The likes of Ferodo or Moog are OEM pad suppliers and the difference in stopping power can be dramatic.
Cheap brake discs don’t have the correct balance between wear and durability.

I do tend to stick with Brembo on my vehicles.

 

[Silver-Fox]

I would be very happy to have pads wearing out at 15k but stopped me with ease. What say you guys ?

If you want soft pads try competion pads, they do varying hardness.

Unfortunately Sprinter brakes are Sprinter brakes.

I know a garage owner that was into his motorsport who had two Sprinters.
He said Sprinter brakes are an acquired taste

 

[pelican]

That doesn’t explain how winding back a calliper air can enter the system

No it doesn't

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[pelican]

Ok so, pads it is, now I fitted brembo disks and pads to my Passat a couple of months ago and I would say it's firm but reassuring. But for my MH I don't want firm. I already have firm but no bite and as already stated I have almost no brake dust, and I really want soft high cold bite pads and to hell with lots of brake dust, I can always clean it off. But I don't want to find myself in trouble next month IN the Alps. I'm thinking jurid - any thoughts ? This is a problem for many of us motorhomers so a definitive answer for us all would be helpful. Most pad makers want pads to last as long as possible but we don't, 30-60k is a lifetime to us, I would be very happy to have pads wearing out at 15k but stopped me with ease. What say you guys ?

Pads on mine have done 181,000m and still ok car has quite fierce braking.

 

[roadwarrior]

A lot of people like brembo pads including myself, but i have mention that while thay are fitted to my passat GTE hybrid, a heavy hector itself, i do have to put some pressure on to make them work, as they do seem to like to warm up first and i want a more immediate bite on my Sprinter based Winchcombe

 

[L' Hobo]

A lot of people like brembo pads including myself, but i have mention that while thay are fitted to my passat GTE hybrid, a heavy hector itself, i do have to put some pressure on to make them work, as they do seem to like to warm up first and i want a more immediate bite on my Sprinter based Winchcombe

Be prepared to spend some money, as I did, go to a proper brake specialist and tell them exactly what you want.
They can supply as there is plenty of choice out there, even ceramics BUT, before that, make sure that the rest of your system is working correctly!

 

[badger123]

Where does the air get in? I thought when you squeezed the calipers back, the fluid it just went back to the reservoir?

Correct Pushing pads back will not cause air in the system