Bleeding Brakes!

[400-ascona]

Just rebuilt the master cylinders on the 1963 Silver Cloud III. Cleaned the reservoirs and replaced the flexible pipes on the feed side.

Struggling now to get them to pump any fluid. The design of the master cylinder is very similar to the RD250 I recently rebuilt. I struggled with that too! Eventually I used a pressure bleed system which required drilling a spare reservoir cap. I don't have that luxury on the Rolls-Royce.

Does anyone have any experience of bleeding these things? How do you get the master cylinders primed and pumping?

Rob

 

[CompoSimmonite]

I use a Mityvac for bleeding brakes. Sucks fluid through bleed nipple rather than pushing from master cylinder.

Paul H

 

[markcantweld]

The only time I really struggled to bleed a similar system it was a clutch slave cylinder, after having replaced the hydraulic hose. It had a horrible air lock and just wouldn't pump. I ended up injecting fluid in through the bleed nipple with a syringe to force the air back to the master cylinder. Bled up a treat after that.

 

[400-ascona]

Just tried a jam jar with the pipe going into an inch of fluid and a vacuum over a hole in the lid to get a vacuum going in the jar. Still no joy.

Might try injecting into the master cylinder but they are both under the floor between the chassis crucifix so wont be easy.

Rob

 

[Robotstar5]

I got a Gunson eezibleed kit many years ago, it came with a selection of caps for the reservoir.

 

[CKJDJK]

If you can clamp a piece of inner tube complete with valve over the filler using a jubilee clip then you could pressurise the resoivour using bicycle pump or similar. Dont let the resivoir empty though or you will need to start again. It would work same as the gunson kit but without the extra bottle of fluid. I have used this method when my gunson kit does not have the right cap.

 

[madkayaker]

Last time I did any brakes I used a fresh oil pump can length of hose and back filled the system

 

[langy]

Its much easier if you bench bleed the master cylinder first

 

[normspanners]

When you undo the nipples on either side is fluid running out if it is not, the piston in the master cyl could be stuck if dual then only one side may be running that means one ellement is stuck, what you have to do then is whilst tapping the master cyl lightly is just move the brake pedal a very small amount repeatedly maybe only 25mm or so until you feel the pressure start to build up. then very sharp jabs of the brake pedal with both sides nipples open.
That forces the fluid and air out in jerks but allows the pistons to return fully.

 

[Marc.]

Hi, being involved with classic and american cars, we have got away with some tricky bleeding jobs using a Sealey VS020 - Brake & Clutch Bleeder Vacuum Type system. Quite cheap and definately worth the investment in my opinion. Others will say differently most likely but its all i could afford at the time and has turned out to be rather usefull!

Marc

 

[400-ascona]

I got a Gunson eezibleed kit many years ago, it came with a selection of caps for the reservoir.

Good suggestion. We didn't have a cap that would fit, but did find a way that I will put up later when I have had a shower and some dinner!

Rob

 

[400-ascona]

If you can clamp a piece of inner tube complete with valve over the filler using a jubilee clip then you could pressurise the resoivour using bicycle pump or similar. Dont let the resivoir empty though or you will need to start again. It would work same as the gunson kit but without the extra bottle of fluid. I have used this method when my gunson kit does not have the right cap.

I really like this idea and would have used it if I hadn't already worked it out.

Will keep this one in the good idea bank.

Rob

 

[400-ascona]

Last time I did any brakes I used a fresh oil pump can length of hose and back filled the system

We thought about going this route too but didn't have anything suitable to pump with.

Rob

 

[Exuptoy]

Hi, being involved with classic and american cars, we have got away with some tricky bleeding jobs using a Sealey VS020 - Brake & Clutch Bleeder Vacuum Type system. Quite cheap and definately worth the investment in my opinion. Others will say differently most likely but its all i could afford at the time and has turned out to be rather usefull!

Marc

Use one myself, superb and only £20 odds on the bay of E

 

[400-ascona]

Its much easier if you bench bleed the master cylinder first

This was an option. Getting the cylinders up into the chassis wasn't easy. If I had thought on before I would have done it, but taking out the assembly and starting again was bottom of the list of want to try.

Next time I will definately prime on the bench.

Rob

 

[400-ascona]

Hi, being involved with classic and american cars, we have got away with some tricky bleeding jobs using a Sealey VS020 - Brake & Clutch Bleeder Vacuum Type system. Quite cheap and definately worth the investment in my opinion. Others will say differently most likely but its all i could afford at the time and has turned out to be rather usefull!

Marc

I guess this is like the Mityvac. We did try a home built version using a glass jar and a vacuum, but no joy. It did work well on the front brake of my RD250 last time I used it.

Rob

 

[ytre]

Get a vacuum bleeder rob, just open the nipple and it sucks the fluid through. U'll wonder how you ever managed without it

 

[rory1]

I have a small garden presurised sprayer that I fill with fresh brake fluid and attached a length of hose to. Stick the hose on the bleed nipple ( once you've cleaned the nipple thoroughly) and back bleed the system. http://http://www.diy.com/nav/garden/garden-care-watering/watering-irrigation/hand_sprayers/Hozelock-Pressure-Spray-1-25L-9956458?skuId=10377163

You have to watch to make sure the master doesn't overfill when back bleeding. I suck out the fluid with a big syringe.

 

[Wallace]

I have an air operated vacuum bleeder like the one below. They tend to draw air past the bleed nipple threads, coating the threads with red brake grease to seal them helps. I also have one or two bleed nipples that are drilled through for bleeding dry systems.

Also works well for bleeding cooling systems, sucking oil out of cylinder head bolt holes etc.

 

[400-ascona]

Struggling to get the pictures off the phone. For now here is one of the car we were working on:

Rob