Bedford MK Brake Bleeding

[billgatt]

I have a 72 Bedford MK with 500 diesel and 5 speed box. Truck has been sitting a while (dry storage) and developed a burst brake pipe. Ive fixed the pipe but now cannot get the air or for that matter fluid to come through the system. I topped up the resevour with fluid (the one supplying front brakes) then opened the bleed nipples but cannot get fluid to come through. Ive tried pumping the pedal but with no success. I also tried jambing the brake pedal down and then opened the bleed nipple thinking it would gravity bleed but again no succes. Any thoughts or advice?

[mylesdw]

I think the pedal needs to be UP if you want to bleed by gravity; it is the only time the reservoir is directly connected to the wheel cylinders.

What sort of braking system is it? Is it air/hydraulic (see picture) or vacuum/hydraulic? I'm guessing the former for a diesel-engined vehicle in which case pumping the pedal up and down will have no effect without air pressure in the tanks.

Bleeding by gravity alone is probably not practical due to the twists and turns in the pipework (especially front nearside).

There are various tools you can get that (slightly) pressurise the reservoir and these work well.

[teachertom]

hi any ideas guys pls
went to bleed the brakes on appliance yesterday again as they didn't seem quiet right backs bled ok fronts wont bleed at all have checked t the reservoir end and none come out of the unit when you push down the pin inside the reservoir so not sure if that is faulty or how they fully work so i maybe thinking there is a problem with the reservoir when there isn't appliance dosent have hydrovac so all a bit confusing seems to be a blockage maybe for the the front brakes ??? she is a 6 cly petrol engine some one did say it may be the master cylinder thats faulty but back brakes bled ok and the reservoir emptied im guessing the front reservoir works independently in the cylinder she is air over hydraulic by way


cheers tom

[mylesdw]

I can't really understand your post with so little punctuation and I don't know what 'hydrovac' is. Can you explain further?

[coachman]

Originally Posted by mylesdw

I can't really understand your post with so little punctuation and I don't know what 'hydrovac' is. Can you explain further?

A Hydrovac is the name given to a vacuum assisted brake booster. Most T.K's would have had air over hydraulic brakes - but as this vehicle has a petrol engine it most likely has a vacuum assisted system.
It's been a long time since I last worked on a vehicle like this but I think the engine will have to be left running in order to bleed what ever system it has. Also if it has a Hydrovak the hydraulic side of this will need bleeding before bleeding the wheel cylinders. As already stated, my experience of these vehicles is very dated and it's all a bit hazy now. If I was actually there doing the job - no doubt it would all come back to me.

[hotel magnum]

as the master cylinder is a two compartment system you should start to bleed the system from the rear if the repair was at the front brakes, and at the front if the repair was to the rear wheels, starting with the wheel farthest from the master cylinder, obviously you will only get fluid from the wheels not under repair as no air has been allowed to enter that half of the system, then progress to the repaired section using the farthest wheel, this will have allowed the pressure to equalise in the master cylinder, and bleeding should be achieved