Reverse Bleeding works for Brakes as well!

[Bumpa]

I have used reverse bleeding several times for hydraulic clutches with 100% success, but today I did my 1850's brakes with it. The system is entirely new with new master cylinder, calipers, rear cylinders and pipes and flexibles, so it was the ideal time. I filled the Eezibleed with fresh brake fluid, connected it to the rear bleed nipple, and pressurised it with a tyre with less than 10 psi pressure. I had previously opened both front caliper bleed screws and attached a short tube from each into a jar, and the master cylinder had its cap off.

As soon as I connected the tyre valve I saw the fluid travel up the clear tube and into the rear nipple. Then for what seemed like ages nothing happened, but then I noticed a small trickle of fluid coming out of the RH caliper screw. I checked that the flow was steady without bubbles and then tightened that nipple. Shortly after, the same thing happened on the LH caliper and again when the flow was steady I closed that one off.

Then, as if by magic, the master cylinder reservoir began to fill from the bottom up. Once it was about a third full, I closed off the rear bleed screw and depressurised the Eezibleed bottle.

Opening the door of the car I tentatively put my foot on the brake pedal. What do you know, it went down about half way and was then solid. I jammed it down with a timber baulk and tried each brake to find all were locked on. RESULT.

When you work alone, as I do, this was a brilliant solution to what is often a two man job. Do give it a try, it really works. I just wish it was me who had thought of it, but sadly I'm just copying someone else's genius.

[trackerjack]

It would be interesting when someone tries this on the Sprint clutch as most seem to have bother with this little nuisance.

[yorkshire_spam]

I've always been a bit wary of reverse bleeding, I was told dire things about damage to master cylinder seals etc. and it put me off. Not sure if there's any truth at all in it, probably just superstition.
For solo bleeding I tend to use the 1 way valves you can attach to the bleed nipples.

[Bumpa]

I've always been a bit wary of reverse bleeding, I was told dire things about damage to master cylinder seals etc. and it put me off. Not sure if there's any truth at all in it, probably just superstition.

I really can't see how it could damage seals. The fluid is not being pushed past the seals, it is simply filling the cavities, and the pressure used is extremely low when you consider what can be generated through the pedal. The great advantage is that the air is being pushed upwards, the way it naturally wants to go.

Regarding bleeding clutches, I have used this technique on MG Midget, MGB, V8 MGB, Lotus Elan, and now on the Dolly 1850. Has always worked first time every time. It helps to have the system empty when you start. This is the first time I have tried it on brakes.

[tinweevil]

I've always been a bit wary of reverse bleeding, I was told dire things about damage to master cylinder seals etc. and it put me off. Not sure if there's any truth at all in it, probably just superstition.

It is. This method takes advantage of the valve that has to be there to allow fluid back into the reservoir when you push the caliper pistons back to fit new pads.

Top tip thanks Bumpa, I've used reverse bleed on clutches but never thought to try it on brakes.

[new to this]

How would you reverse bleed a clutch

Thanks Dave

[yorkshire_spam]

How would you reverse bleed a clutch

Thanks Dave

You try to put the car in reverse and when the clutch doesn't work you shout "Reverse! Bleeding Clutch!"
Or... you pump hydraulic (brake) fluid under (fairly low) pressure in through the bleed nipple on the clutch slave until it starts filling the reservoir.

I'm not sure which?

[Bumpa]

How would you reverse bleed a clutch

Thanks Dave

Exactly the same way I described for the brakes at the top of this thread. You need a Gunson's Eezibleed kit. Start with the clutch master cylinder empty. Get your spare tyre and let the pressure down to between 5 - 10 psi. Any more than 10 and it goes too fast to control properly.

Fill the Eezibleed bottle with brake fluid. Connect the bottle outlet with a tube to the clutch bleed nipple. Connect the other side of the bottle cap to the tyre valve - it comes with a tyre connector on it. Open the bleed nipple just a little. Fluid will be pushed in through the bleed nipple, up the pipe and will appear in the master cylinder. Once it is about half full, close the bleed nipple and disconnect the kit. You should have a working clutch.

[new to this]

How would you reverse bleed a clutch

Thanks Dave

You try to put the car in reverse and when the clutch doesn't work you shout "Reverse! Bleeding Clutch!"
Or... you pump hydraulic (brake) fluid under (fairly low) pressure in through the bleed nipple on the clutch slave until it starts filling the reservoir.

I'm not sure which?

thanks Dave

[new to this]

How would you reverse bleed a clutch

Thanks Dave

Exactly the same way I described for the brakes at the top of this thread. You need a Gunson's Eezibleed kit. Start with the clutch master cylinder empty. Get your spare tyre and let the pressure down to between 5 - 10 psi. Any more than 10 and it goes too fast to control properly.

Fill the Eezibleed bottle with brake fluid. Connect the bottle outlet with a tube to the clutch bleed nipple. Connect the other side of the bottle cap to the tyre valve - it comes with a tyre connector on it. Open the bleed nipple just a little. Fluid will be pushed in through the bleed nipple, up the pipe and will appear in the master cylinder. Once it is about half full, close the bleed nipple and disconnect the kit. You should have a working clutch.

Thanks ill give that a try

Dave

[sprint95m]

Whilst it may be okay on a Dolomite......

I've always been a bit wary of reverse bleeding, I was told dire things about damage to master cylinder seals etc. and it put me off. Not sure if there's any truth at all in it, probably just superstition.

I really can't see how it could damage seals.

Before you push the pistons back on any ABS braking system you should open the bleed nipples to stop the fluid going backwards, as it were.

Non ABS brake master cylinder seals on various Vauxhalls can't take reverse bleeding either.



A simple foolproof bleeding method, albeit a slow one, is to open the bleed screws and allow gravity to do what it does best.




Ian.

[Bumpa]

Whilst it may be okay on a Dolomite......

I really can't see how it could damage seals.

Before you push the pistons back on any ABS braking system you should open the bleed nipples to stop the fluid going backwards, as it were.

Non ABS brake master cylinder seals on various Vauxhalls can't take reverse bleeding either.



A simple foolproof bleeding method, albeit a slow one, is to open the bleed screws and allow gravity to do what it does best.


Ian.

Ah well, I only work on old cars. I have two cars with ABS but they can go to a garage for work in that department. I've never tried the gravity drip method. Must give it a go some time.

[dollyman]

I have got to agree with the "gravity" method I have always done it that way if working on my own

Cheers,
Tony.

[AlanH]

I use this Little Bleeder
https://www.ebay.co.uk/itm/New-Motorcyc ... SwAQBZuiUq

Works like a charm

[Robert 352]

I am grateful for Mike/Bumpa for his suggestion of using the Eezibleed device for reverse bleeding his brakes for it is suggestions like this which can make tasks for some of us so much easier. I would encourage others who have similar ideas, or adaptions of techniques to make life that bit easier for us all, to share them.

AlanH’s suggestion of using the little one way valve thing used for bleeding motorcycle brakes looks fairly smart too.

There is another thread running just now about the extraction of the remains of a spark plug in the head. When the solution to that is found in the case of Alun/xvivalve’s little problem perhaps the technique that works for him can be published too.

But back to bleeding the brakes single handed.

It is a problem which I have had to do on a number of occasions for my favoured method of removing the engine from a Dolomite or Toledo is to simply drop the entire engine and gearbox sub assembly out from underneath the car on the sub frame. It means though that I must put new fluid through the brake lines for the front brakes have to be disconnected from the body. I regard brake fluid as something that should be changed regularly so do not mind sacrificing the brake fluid when I remove the sub frame.

Whilst I would love to have access to equipment like the Eezibleed my technique is simple and effective too.

I have a piece of wood which is 19 inches long, which is about 480mm on Jeroen’s tape measure. Pump the brake or clutch pedal several times and then wedge the wood between the pedal and the ridge in the floor below the seat. If you are doing the brakes, bleed the left rear first and then work around the car. You need to pump the pedal and wedge it a few times, and pour in fresh fluid into the reservoir as required. It does not take all that long before the pedal firms up and you know the job is done. I have a piece of plastic tube which I push over the bleed nipple which came from the local hospital for it has a nicely flared end on the end which passes over the nipple, and the tube passes happily through a 7/16 ring spanner.

My technique allows me to see when the fluid runs clear of any air bubbles although I do like to go back and give each nipple another bleed some hours later just in case there was a small amount of air still trapped somewhere. And generally I have the car up on axle stands with all the wheels off so that I do not have to crawl around on the garage floor.

Thanks Mike and Alan and thanks too to Ian for his equally simple suggestion of allowing gravity to do the job.

Robert