Long Wheel Base Brakes

[jdobson]

There's been air in my braking system for way too long and I'm tired of having to pump the peddle at least once before I get decent pressure. I have also found my rear flexible hose has deformed - there are bulges clearly visible even when not under load. Oh and the brake pressure switch is broken so it's time to try and sort this out.


Does anyone have any amazing tips on how to bleed the system? I'm thinking, replace the bits that need sorting, clamp the front two flexible hoses and bleed the back cylinders with an assistant pumping the peddle. Once happy with that, clamp the rear hose and do each front wheel in turn (removing the clamp for each wheel and putting it back on upon completion and moving to the other side). I also heard that for the front wheels you should take the drums off and, using a ratchet strap, tighten the brake shoes down so they are fully depressing the brake cylinders? Oh and back the snail adjusters right off?


Any tips, words of wisdom would be greatly appreciated. Thanks!

[JDNSW]

I know some people have a lot of trouble bleeding these, but I never have. Often the need to pump the brakes is not necessarily air in the fluid - it can reflect incorrect adjustment, snails worn, incorrect return spring location, or faulty hoses. Air in the fluid will always give spongy brakes. If pumping gives you a hard pedal, air is not the problem.

Your procedure should work, but in the event of problems, remember that you can bleed from any union. It is also simple and easy to reverse bleed, using a clean oil syringe to inject fluid into the bleed nipple. This has the additional advantage of only needing one person. Just make sure you don't overflow the reservoir. Clamping off all hoses except the one feeding the wheel(s) you are working on is good practice.

John

[gromit]

Does anyone have any amazing tips on how to bleed the system? I'm thinking, replace the bits that need sorting, clamp the front two flexible hoses and bleed the back cylinderswith an assistant pumping the peddle. Once happy with that, clamp the rear hose and do each front wheel in turn (removing the clamp for each wheel and putting it back on upon completion and moving to the other side). I also heard that for the front wheels you should take the drums off and, using a ratchet strap, tighten the brake shoes down so they are fully depressing the brake cylinders? Oh and back the snail adjusters right off?


Like John I don't have problems bleeding Series brakes, well OK the Series I was a bit of an issue.

I don't think clamping off the lines will do anything unless the shoes aren't properly adjusted to start with. Likewise with the ratchet strap on the front shoes, if adjusted properly I can't understand what you'd gain by doing this.
If a bleed nipple is opened there wouldn't be enough pressure in the system to operate the brakes you aren't bleeding anyway so clamps/straps wouldn't be needed.

I get one of my young blokes to help but I've also used one-man brake bleeders with great success.
On the Series I we had an air bubble trapped somewhere. The Father-in-Law solved the problem using two different methods.
1st, hose onto nipple, hose into a jar, open nipple then he stood on the pedal fast and with maximum force.
2nd, hose onto nipple, hose into a jar, he then opereated the pedal a number of times and kept it depressed before the nipple was opened.

Both the above cause a rapid exit of fluid and tend to drag any trapped air bubbles out of where they are trapped. The above plus a combination of normal bleeding got a firm (well firmish) pedal.


Colin

[chazza]

1st, hose onto nipple, hose into a jar, open nipple then he stood on the pedal fast and with maximum force.

Colin

This is the only method I have ever needed to use and it has always worked; the only difference is, that I call it stamping and Land Rover called it depressing smartly :D

Cheers Charlie

[jdobson]

Well it didn't work.. the peddle felt firm but after a short time it lost pressure and felt spongy. I think I need to give it another go. I have heard that you need to back off the adjusters on the front wheels and clamp the wheel cylinders in the closed position as air can accumulate in the top of the system (I didn't have time to do this). I like the idea of injecting fluid from the nipple end, shall give that a go on my next attempt.


At least I have now replaced the rear flexible hose, the old one was really badly deformed with bulges all along its length. I also attempted to replace the pressure switch in for the brakes but turns out the replacement was the wrong size - of course taking out the old one didn't exactly help my air in system issue! I ended up setting up a new switch that operates directly off the brake peddle.. that, combined with new genuine Land Rover tail lights means at least my lights work (even if the brakes don't...)..


Two weeks until I drive to Adelaide from Sydney so I better get the brakes sorted... along with various other issues that might throw a spanner in the works (fuel gauge only reads when full or 3/4... topping up everything with oil... sorting the slight exhaust leak... resetting the points... cleaning the sparkplugs... etc. etc...)....


On the plus side, my girlfriend was happy to help pumping the brake peddle and I didn't object too much when she pressed too hard and I ended up with brake fluid in my face...

[Ozdunc]

Get one of the brake bleed kits with the one way valve. They're so easy to use single handed.

Attach to nipple, put end in jar, open nipple, push pedal til happy. You need to keep hopping out to top up the reservoir etc

I've had mine for years, but should be ~$20 from your local auto supamarket

[Aaron IIA]

The compression barrel and centre valve master cylinders each have a different bleeding process. Which do you have?
An alternative sure and easy method I have used to bleed brakes, is to use a weed sprayer. Drill a hole in a spare master cylinder cap and solder on a 1/4 or 5/16 hose barb. Connect this to the hose from the weed sprayer. Partially fill the weed sprayer with brake fluid and apply a low pressure. Open a slave cylinder nipple and bleed until clear fluid is emanating.
Aaron

[Aaron IIA]

Like John I don't have problems bleeding Series brakes, well OK the Series I was a bit of an issue.

I found it easier to bleed the SI brakes. Operate the bleed nipples with your hands, operate the brake pedal lever with your leg, all while below the vehicle. No assistant necessary.
Aaron