Reverse bleeding brake system

[Veryan]

Hi Everyone,

Has anyone tried reverse bleeding the brake system - by using a syringe to pump the brake fluid up into the reservoir and thus encouraging any air bubbles to rise, rather than trying to push them out?

It was an old trick we used to use when I worked in a bike shop.

Downside, very messy, but usually can be accomplished by one person.

Any thoughts on the matter?

James

[bee utey]

With disc brakes all you need to do is retract the piston/s manually before fitting new pads, does the bleeding back up to the reservoir without mess:). A bit more difficult with drums, you need a bleed screw with an O ring on the thread to do it properly.

[zulu Delta 534]

Over the years I have found the simplest and most foolproof one man system of bleeding Land Rover brakes requires some very basic equipment.
1 x Glass jar with a sealable airtight lid.
2 x lengths of plastic or rubber tubing. (Hospital drip tubes are ideal or plastic line is available from most hardware stores.) Ensure that the inside diameter of the tubing forms a nice tight fit over the bleeder nipple!!
Drill two holes in the lid of the jar corresponding to the o/d of the tubing that you are using.
Disconnect the car vacuum tube from the carby then fit the longer of your plastic tubes to this suction point. (This tube should be long enough to reach unhindered from your car engine to all wheels of the car!) The other end of the tube then goes through the lid of the plastic jar (ensure an airtight seal - perhaps silastic. Fit it so it sucks from high in the bottle as you dont want to be sucking purged fluid back to your carby!)
Fit the second and shortest tube through the second separate airtight hole in the lid on the jar. (This tube goes from the jar to the bleeder nipple on the car so only needs to be a couple of feet long, so that you can see the purged fluid level whilst you work.)
Test the system now by starting the engine of the car and checking that there is suction at the end of the second tube. Please excuse the artwork.
https://www.aulro.com/afvb/images/imported/2011/01/972.jpg
Next, apply a ring spanner of the correct size to the bleeder screw, fit the vacuum hose to the bleeder nipple, undo the bleeder slightly and watch the bubbles and fluid being sucked into the jar. When a solid flow of fluid is flowing, close the bleeder and remove the suction tube.
Repeat this operation on the four wheels ENSURING that the fluid reservoir system is topped up periodically!
This system operates in basically the same way pressure bleeding works but has the added advantage of the vacuum not only sucking the fluid through the lines but also sucking air through the lines whereas pressure bleeding simply compresses the air and the fluid often bypasses it.
Don't forget to replace the vacuum control line back to the carby on completion of the job!
Try it, all you can lose is the price of the tubing and possibly one of Mum's favourite glass jars.
Plastic jars do work but tend to buckle under vacuum.
Regards
Glen

[Veryan]

Thanks heaps for that little gem of advice.

I don't have any vacuum assisted brakes on my diesel landy, but using the same principle, I either need to tap that vacuum line into the inlet manifold/intake or connect it to some form of vacuum pump to achieve the same effect?

Do you clamp off the other three brakes at the flexi hose end and just work on one at a time?

[bee utey]

Thanks heaps for that little gem of advice.

I don't have any vacuum assisted brakes on my diesel landy, but using the same principle, I either need to tap that vacuum line into the inlet manifold/intake or connect it to some form of vacuum pump to achieve the same effect?

Do you clamp off the other three brakes at the flexi hose end and just work on one at a time?

You would not need to clamp the other 3 lines, so long as their bleed screws were shut. For vacuum, borrow someones car to idle next to your truck, or plumb up a lawnmower or something similar.:)

[ezyrama]

Thanks Zulu that's so simple it's almost too easy. Gotta do Ralph the 2a when I find out why there is no pedal pressure (it was ok 2 months ago).

Cheers Ian

[zulu Delta 534]

It is so simple and also pretty foolproof.
People often complain about a pocket of air always getting trapped in a high spot and how one should park on a steep slope etc but using this simple system the results, provided the rest of your system is OK, are pretty well always spot on.
This was passed on to me years ago by a good mate who is no longer with us, so the best I can do is pass it on.
Regards
Glen

[ezyrama]

I was actually thinking of using a vacuum pump and an old set of refrigeration gauges but now I dont have to risk contaminating my old tools of trade.
Cheers Ian

[Disco44]

Thanks for that.When I had series landies,the amount of time I took to bleed brakes was out of this world.Even then I never really finished up with a good pedal.So thanks again I've got my eye on a series 1 for a future project.

John.

[TJWA]

With mine I have bought a long piece of clear hose just big enough to fit over the brake bleed screws and long enough to get back to the brake fluid resivior (mmm spelt wrong isn't it). I then just pump like mad for a couple of minutes, come back in an hour and pump some more. I then put on some good dance music and pump some more in time to it.:twisted:

[subasurf]

It is so simple and also pretty foolproof.
People often complain about a pocket of air always getting trapped in a high spot and how one should park on a steep slope etc but using this simple system the results, provided the rest of your system is OK, are pretty well always spot on.
This was passed on to me years ago by a good mate who is no longer with us, so the best I can do is pass it on.
Regards
Glen

I might give this a go over the long weekend...maybe. I've even got a small 3hp old Briggs and Stratton engine sitting around. Might use that to create the vacuum. Thank you and your mate for the advice :)

[Hardchina]

You also do the same by pressurising the master cyl reserviour. I made up a spare tank cap with an air line that went to a garden sprayer jigger. Worked well.