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Hi all.
My Hijets failed the MOT on the rear brakes. There reistering zero on the divers side and around 30 on the passenger side. The wheel cyclinders aren't showing any signs of leaking. My Hijet has had a front end so this may be significant. The master cylinder is showing fluid on the white plastic cap under the grey rubber cover.
I'm also dubious about the load sensing valve. I've picked one up today from a scaper, hopefully I'll get it on tommorrow.
I'm wondering whether I can bypass it using a block for the 3 pipes to go into rather than through the LSV.
Why does the LSV have 2 inputs and only 1 output to the drivers side rear wheel, which then rather than a bleed valve has a brake pipe to the passenger side wheel, this then has the bleed valve.
Would it be workable to have these three pipes screw into a block?
I'l have to get a manual of Harvey!
Thanks
Vertical
Bleeders
Check the master cylinder for a bleed nipple or drain plug, if it has one, open it and drain the fluid through to ensure both pistons in the master cylinder have fluid within them.
On the load sensing valve, look for a lever connected to the body, this opens the valve dependent on weight, pull it right down, and sprag it in this position, it will allow full flow to the rear wheels.
Bleed the brakes as normal, noting any air coming out, if no fluid or air comes out, the load sensing valve may be siezed, or defective. Move to the front of the vehicle, get an assistant to hold the brake pedal down, loosen the rear brake feed pipe on the master cylinder to see if it is working, if not the master is knackered.
Finally, check all flexible hoses, as these can deteriorate and become internally blocked, although rare, I have had it on occassions.
Hi assassin. Ive only just
Hi assassin.
Ive only just seen your reply so it will be tommorrow at the earliest that I can have a play again.
From the last time I tried I removed the brake pipe between the two rear wheels as it looked crushed. I bled them afterwards with plenty of air coming out after replacing with a new pipe, the fluid followed after a while. I was hoping this would solve the problem but it didn't. After doing this I could see a slight movement around the load sensing valve when the brakes were pressed.
The bleeding of the master cylinder sounds like something I should get onto as my van has had a light front end. When I got it I had to force the front panels ( bulkhead?) forward as the damage was stopping the brake pedal returning so the brakes were locked on.
Thanks again.
P.S. Are the wheel cylinders unusual because one company said they'd had problems with customers they had supplied to and that they were dealer only? (Andrew Page by the way)
Thanks
Vertical
Hi Andrew
As you have stated you have a vehicle with a front ender, I would suggest checking the stroke on the master cylinder, if the brake pedal does not forwards enough, it will operate the front piston, but not have enough travel to fully operate the rear piston inside the master cylinder.
Check by getting someone inside the vehicle, and holding down the brake pedal, crack the rear line brake pipe nut, and tighten it again. get them to release the brake pedal and re press it and hold it down, crack the nut again. This will bleed the cylinder, and allow you to judge if the master cylinder is knackered.
Master cylinders generate between 1200 psi - 3000 psi, so be careful.
Hi Assassin. Thanks for the
Hi Assassin.
Thanks for the more detailed instructions to bleed the master cylinder.
Yesterday was the last day for the MOT retest, so with the scrap yard load sensing valve fitted and the system bled it went back but with around 250 kg of scrap metal in the back.
It passed registering 70 and 80 on the back wheels so I won't be bleeding the master cylinder. Do they seriously generate 1200 - 3000 psi? I'm glad I don't have to mess around with it with that sort of pressure.
So, I think the original LSV may have even worked with that much weight in the back. These Hijets rear brakes must barely work under normal driving conditions without any load in the back! I did read a thread om here about adding weight to the back and I should have taken heed earlier although I did expect such a significant increase!
Thanks Again
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