Morning all Merc sprinter rear brakes on a camper van

[lotus 30]

Testing a theory
Camper van the load over the back axle operating the rear brake loading valve is fairly constant IE pretty well fully loaded van so the Valve should be operating the rear brakes pretty close to max pressure. Now my camper has air bag assist i usually inflate to 50 PSI in doing so i raise the ride height so less back brake the rear discs are rusty due to lack of use. And to be hones the brakes on the van could be better. All four callipers are working well and not sticking using apec pads all round. comments welcome.
Andy

 

[Bobupndown]

How does raising the ride height affect the brakes, still the same weight on the axle?

 

[carbon]

How does raising the ride height affect the brakes, still the same weight on the axle?

I expect the load sensing valve has a mechanical link to the axle, so increasing the ride height reduces the rear brake effort.

If the load doesn’t change much you maybe able to adjust the length of the link to increase the rear brake effort

 

[lotus 30]

How does raising the ride height affect the brakes, still the same weight on the axle?

It has a proportioning valve operating the rear brake pressure to stop the rear wheels locking under light load.

 

[lotus 30]

I expect the load sensing valve has a mechanical link to the axle, so increasing the ride height reduces the rear brake effort.

If the load doesn’t change much you maybe able to adjust the length of the link to increase the rear brake effort

Yes as my thinking it does have a lever system from the axle. I need to find out more before messing with some thing I only have limited knowledge on

 

[qwakers]

30 secs on google and...

Load apportioning valve adjustment after fitting air shocks

Hi, I have a 1999 Mercedes Sprinter 310 LWB. It's a camper conversion that I've done. She's therefore driving around with a heavy load all the time, gas, water tanks etc. It's a proper conversion, not just a mattress in the back. So I fitted air suspension. Between the rear leaf springs...

sprinter-source.com

 

[lotus 30]

30 secs on google and...

Load apportioning valve adjustment after fitting air shocks

Hi, I have a 1999 Mercedes Sprinter 310 LWB. It's a camper conversion that I've done. She's therefore driving around with a heavy load all the time, gas, water tanks etc. It's a proper conversion, not just a mattress in the back. So I fitted air suspension. Between the rear leaf springs...

sprinter-source.com

ha ha yes just read it thanks still not sure if the valve needs to be fully back or forward to allow full pressure

 

[hotponyshoes]

Just deflate the air assist and see where the valve sits.
Then reinflate to the ride hight you want and look again then lengthen the link bar to put it in the same place

 

[qwakers]

This^^^^^

 

[lotus 30]

Just deflate the air assist and see where the valve sits.
Then reinflate to the ride hight you want and look again then lengthen the link bar to put it in the same place

Dam thing is on axle stands axle is on full droop just now ok just gathering information just now no rush on this not away for a wile

 

[Bullet2012]

Beat modification to a camper van is the for sale advert. Then take the nearest offer to the asking price and utilise the funds to stay in decent hotels.

 

[lotus 30]

Beat modification to a camper van is the for sale advert. Then take the nearest offer to the asking price and utilise the funds to stay in decent hotels.

Not a chance wife loves the thing LOL.

 

[lotus 30]

Posting on here helps me work through how it is supposed to work. The mechanical lever system is a limiter the valve moves forward when the brakes are applied the more weight in the van I assume the more it travels allowing more pressure to the callipers. it moves about 1/4 inch. Some good clever people on this forum the answer will appear I have the faith.
Andy

 

[hotponyshoes]

Have you actually tried driving the van yet?
Find an empty bit of road and try a few emergency stops.
You might find it's fine as it is.
You want the front wheels to lock up and then it should take a fair bit more effort on the pedal to get the rears to lock up as well.

If you have kitted the van out right up to the weight limit for the rear axel and will be keeping the weight pretty much the same then you could just disconnect the valve link and lock it to the maximum position as its the weight that makes the difference not the ride height.
Unless you have a lot of weight on the front axel as well and the van Nose dives under breaking but you'll probably find the valve is not responsive enough to compensate for that under emergency conditions anyway.

 

[MoreWellie]

You want the front wheels to lock up and then it should take a fair bit more effort on the pedal to get the rears to lock up as well.

not disputing but if the front wheels lock you lose steering ability, why would you not want to get the maximum braking from all wheels before any of them lock

 

[bricol]

not disputing but if the front wheels lock you lose steering ability, why would you not want to get the maximum braking from all wheels before any of them lock

I think the point he is making is you do not want the rears to lock first!

If they do, you are doing a quick 180 directly to the scene of the accident!

 

[lotus 30]

All very valid points
Ref lock front wheels not a chance the brakes pass MOT easily if I brake for say a round about the brakes pull up ok but if I ask for more it's not there under foot. I need to find out if the valve works full rear when it is back or when pushed forward under braking. I have changed the front pads for Bosch. To try them against the Apec I have also bled the system on all four wheels. I just need to understand how the rear valve wants to operate. Just giving it a good service before this season I also tow my lotus with this van but the trailer brakes are spot on and no problem.

 

[mike 109444]

I think you will find IF you "tamper/modify" the mechanism that would be an MOT fail. Think some estate cars have this mechanism. So you might find more descriptions of how it works by searching that avenue maybe. Does your vehicle have a servo. Could be that's poorly if the brakes are lacking punch.

 

[bricol]

Poorly servo is usually obvious - rock hard pedal and slightly better than naff all effect on speed . . .

 

[carbon]

I think you will find IF you "tamper/modify" the mechanism that would be an MOT fail

How would the examiner know that it has been adjusted from the factory setting?

When I lowered my VW T4 they can be prone to locking the rear wheels due to the different ride height with little weight in the rear. The common fix for this is to replace the two springs that act upon the load sensing valve with some from a different model. It looks identical but doesn’t apply as much effort to the rear brakes.

I would expect that if this valve was replaced due to being seized for example that the replacement would not be set correctly from the factory and would required to be set on the vehicle