Brake Problems

[caemadoc]

Hi, I am having some brake issues on my 2.4 LN130. Started off with dash brake light appearing on start up. After a few seconds it would disappear. Checked fluid level which was a bit low so topped up, problem disappeared for month or so, then returned. Fluid level was fine this time, so guessed it must be pads/shoes. I duly fitted new Pads and Shoes all round, drums and discs looked ok. Gleefully jumped aboard the truck and found no change!

Today I have bleed the brake system and slight change! (Although brakes couldn't stop a draft!)

What seems to be happening now is dash brake light only comes on when brake pedal is pressed down, light stays on until engine is reved. I have looked round master cylinder and servo and cannot see any fluid loss, it's kind of like a loss of pressure somewhere? When pedal is pressed it hits a point and then slowly sinks, but does not pump up to firm.

Anyone had the same or got any ideas??


Cheers

[caemadoc]

Well, I bought another Master Cylinder/servo unit (secondhand) and fitted them today. Also put on new flexi lines and bled the brake system so thats new fluid as well now.

Problem remains the same, if pressure is applied slowly you can feel the brakes actioning, if you go for an emergency stop, the pedal firms up but the brakes don't bite hard down and the dash brake light ignites.

Starting to get the hump with this! There is no fluid loss, the Calipers and wheel cylinder appear fine.

I imagine the load sensing valve at the rear of the truck is there to get a greater brake application at the front end of the car, has anyone had experience of these going wrong.

I am starting to run out of bits to replace??

[BUSHWHACKER]

The LSPV has a bleed nipple too, did you bleed the system from there as well?

The warning light is activated by three different things, fluid level, vacuum and handbrake.

[TonyN]

Sounds like the vacuum pump, the light also comes on if there isn't enough vacuum.

Its part of the alternator.

But also now sounds like its got air in it still, keep bleeding it.

Sometimes the float gets brake fluid in it and sinks, setting the low level warning off. Unplug and try again and see if light goes off.

The light comes for low fluid level, low vacuum and the handbrake switch. It could be any of the above, its NOT connected pads or shoe wear though.

[caemadoc]

Thanks for that, yes I bled load valve as well, sequence I guess is correct if sitting in Drivers Seat would be Rear Left, Rear Right, Load Valve, Front Left and finally Front right, I haven't a manual so if this isn't the right order could someone let me know.

The Vacumn pump sounds like the beastie to me, I have seen the hose running up from the alternator, through a mystery black box (Filter??) and into Servo, the brake light disappears with an increase in engine rev, which is what is guiding me towards there not being enough vacumn in the system, what can I do about this? Any fixes or is it a new alternator??

Many thanks for your help.

[BUSHWHACKER]

If you need an alternator, I have a couple here, £30 each.
I'm near Blackwood.

[caemadoc]

For those who experience a similar problem and to wrap this thread up. It was the Vac.Pump on the Alternator. As I understand it the alternator has a pump built in, which has a pipe arrangement bolted on, mine had come a loose, just a bit, enough to let air in and ruin the whole vacumn thing!! I fabbed up a new copper washer (the original is somewhere in the depths, probably on the oil cooler) and twas sorted!!