Brake Load Sensing Valve questions

[123hotchef]

I know how they work but can I remove it and fit something to adjust the balance manually?
How do they balance the brakes on a normal road car well the older cars before all this abs and traction control mallarky.

 

[hotponyshoes]

Older cars are normally a fixed bias.
Load sensing valves are normally fitted to big vans or pick-up trucks so they dont lock the back end up when they are empty.

It would be simple enough to swap the load-sensing valve with a bias valve (providing you only have one pipe going in/out of the existing valve but you would probably have to run a new line into/out of the cabin but then you could fit a hydraulic handbrake at the same time!

 

[123hotchef]

Older cars are normally a fixed bias.
Load sensing valves are normally fitted to big vans or pick-up trucks so they dont lock the back end up when they are empty.

It would be simple enough to swap the load-sensing valve with a bias valve (providing you only have one pipe going in/out of the existing valve but you would probably have to run a new line into/out of the cabin but then you could fit a hydraulic handbrake at the same time!

there are 3 pipes in the existing LSV, i like the idea of a hydralic hand brake

 

[optima21]

my car originally came with one and the rear axle is a trailing beam axle, there is a linkage connecting the valve (one valve for each brake circuit) to the back axle, so that if it goes light under braking it reduces the load on the rear brake. very simple, but ended up in the bin as it was one thing less to go wrong.

 

[CompoSimmonite]

there are 3 pipes in the existing LSV, i like the idea of a hydralic hand brake

I seem to remember that the handbrake needs to be mechanical and not hydraulic. That doesn't mean, however that you can't have both and just use the mechanical for MOT An umbrella type under the dash would be well out of the way with a hydraulic in normal position between seats

 

[julianthegypsy]

Back in about '99 we had one fail on one our fleet of daihatsu rockys. It felt almost like total brake failure. It still stopped, it just left you gripping the wheel in terror while you waited....

 

[Melvyn Best]

As already stated a hydraulic handbrake is an instant MOT failure , handbrake needs to be mechanical. Also not sure an adjustable brake bias is legal? for IVA purposes any adjustable bias has to be locked and not adjustable from the drivers seat. Different bore wheel cylinders or callipers can be used to good effect but can be expensive

 

[hotponyshoes]

there are 3 pipes in the existing LSV, i like the idea of a hydralic hand brake

That sounds like a split system then? 2 of the lines going to the front and one to one side on the rear with another line between both rear brakes?

My hydraulic handbrake is on a track car so dont need an mot for that!

 

[123hotchef]

That sounds like a split system then? 2 of the lines going to the front and one to one side on the rear with another line between both rear brakes?

My hydraulic handbrake is on a track car so dont need an mot for that!

yes mate that is correct exaclt as u say 2 lines from the front one to the nearside rear cylinder then one from that to the off side

 

[Ruffian]

You can get 4 port hydraulic hand brakes for twin line systems.

Brake bias adjusters help control flow to the rear axle. Usually available in a dial for adjustable or lever for fixed positions.

Quite common on rally and track cars.

Had a few sieze often on the back of 206's and transits leaking.

As said hydraulic handbrake are not road legal to use as "only fixed brake" as needs to be mechanical lock.

 

[fnlvder]

I remember looking at the mot history of a car on ebay (mid 90's passat) , it had failed because the valve was seized then failed the retest because the valve was missing. Worth finding out if its a requirement.

 

[hotponyshoes]

yes mate that is correct exaclt as u say 2 lines from the front one to the nearside rear cylinder then one from that to the off side

That's a bit more tricky then as you need to disconnect the load valve from the axle and fix it in the full position then fit the bias valve into the rear axle line so you will need to run them back into the cabin.
Depending on what the master cylinder is you might be able to remove it and just run one new line to the back.

My hydraulic handbrake can be set to work as normal, it's on a track car so no mot for me but if it had a gator around it I dont think there would be any way to tell it was hydraulic if i wanted to hide it badly enough?

 

[123hotchef]

TBH i do not really need a hydralic HB would be nice. could the bias valve not be fitted under the bonnet and 1 line ran to the rear?

 

[hotponyshoes]

No, you will need it somewhere where you can get to it for it to be any use.
That's presuming you want to fit one to get the maximum braking force available at any time?

If it's just because your existing load valve has packed up then it would be easier (and probably cheaper) to rebuild or replace it.