Ugh, bleeding brakes

Hi Mike

I smiled when i saw your message.I've just finished bleeding my front brake.It's fitted with a RGM m/cyl.

Have you bled the m/cyl. I also stripped the caliper and replaced seals and one piston.Then put in a new bleed nipple

Lots of wasted time using the lever to let air out of m/c into res

In the end i connected 2 metres of 4m/m pvc tube with a small funnel in the top and connected it to the bleed nipple.

Between pumpimg the lever and opening the nipple i got air from both the 4m/m tube and m/cyl.

Also the nipple has to be tight in the caliper because i could see air going up the 4m/m tube when i thought the bleed was closed off.

If this didn't work i was going to use the easibleed,but didn't want to drill a hole in the m/cyl cap.

Any body know of a cap to fit the bleed nipple?

If your local to me i could lend a hand.I'm in the middle of Surrey

Good luck

John

Push both pistons as far back into the calipers as far as they will go ,watch out for overflow at the MC . this may get air moving up .

I have had it before when the lever would not let the piston return all the way out. Try taking off the lever and letting the piston travel right out then pump it with a bar or screw driver then put the lever back on. No guarantee, but worth a try.

Yes , happy memories of trying to get the original Norton caliper working properlyon my Mk1a. In the end gave up and fitted a Norvilupgrade kit consisting of floating disc , Lockheed racing caliper and new hydraulic piping, keeping original master cylinder withnew seals fitted. Tranformed front brake which is nowexcellent. Have since done the same upgrade using the RGM equivalentkit on my Mk3 front brakewith the same positive result.

If you have access to a syringe (about 60ml) you could try pumping fluid into the nipple. Also ensure in this case that the nipple is at the lowest point i.e. remove the calliper and turn it round to achieve this. you will need to get any air out of your connection tube before you begin and it's likely to be a messy business. also beware of fluid overflowing from the master cylinder onto your petrol tank etc.

If you continue with bleeding from the master cylinder it would be worth rigging up some system to elevate the calliper to above the master cylinder to encourage the air to go up.

Boo's advice about the stroke of the master cylinder is also worth attention.

If another Norton has just passed by, transported by Transit due to mechanical disaster, your Commando will respond sympathetically. Treat it kindly and any panic will pass

Paul

Previously mike_sullivan wrote:

my seer says this is because of the transit of a Mercury (why this should affecta Commando I don't know).

Three separate but related problems. poor stock disc brakes, stuck master cylinder piston, hard to bleed system.

My cure for first problem was to find a master cylinder from a Jap singlefront disc setup and use it.Kawasaki works. Only good if you don'tNEED something that looks exactly original.

Second problem, find a good working master cylinder andconnecta brake line from one master cylinderdirectly to the other.with fluid in the good cylinder. The pressure from the good master cylinder when applied will push the stuck piston out.

The third problem requires a compressor and a cheap pressure spray cleaner from your local auto supplythat uses a vacuum hose to draw cleaner fluid through the spray nozzle. hook the vacuum tube to the bleed screw ( this may require adapting slightly different size of tubing) , fill the master cylinder reservoir with brake fluid and use the vacuum to draw the fluid through the system. You may want to place a plastic bag over the spray nozzle to keep the brake fluid mist from getting on everything. Be sure to close the bleed screw before releasing the vacuum pressure.

I had a similar snag on one of my bikes so I know it drives you insane. I finally cured it by replacing the hose...daft I know but who is to say you have not got the tiniest of obstructions??

I resorted to Goodrich hoses and never have had another snag. You can buy in various lengths and fit which ever adapter you require. A company on the A6 in Hazel Grove Cheshire...something like jct300 in the name were great with me and I recommend them no worries. Mine were about £33 all in each......Just maybe the answer Sir?

Previously carl_sanders wrote:

I had a similar snag on one of my bikes so I know it drives you insane. I finally cured it by replacing the hose...daft I know but who is to say you have not got the tiniest of obstructions??

I resorted to Goodrich hoses and never have had another snag. You can buy in various lengths and fit which ever adapter you require. A company on the A6 in Hazel Grove Cheshire...something like jct300 in the name were great with me and I recommend them no worries. Mine were about £33 all in each......Just maybe the answer Sir?

Also discovered the hard way that old gunged up hydraulic pipes can be the cause of bleeding problems. After replacing everything except the hydraulic piping and still not getting proper leveraction and pad release(pads would apply OK but would not release properly)changed the original metal piping for new hydraulic hose and hey presto -great front brake with instant , positive lever response and no pad binding.