Bleeding Rear Brake

[trapezeartist]

No wonder the job is termed “bleeding” because it must be cause of more expletives relating to blood than any other.

I knew it was going to be difficult because I’d already read all the other posts here. I really tried to avoid breaking into the hydraulics but in the end I had to remove and split the calliper to solve the sticking pistons. I tried reverse bleeding: no result. I tried pumping like you would with a car: no result. I went back to reverse bleeding, did lots of tapping on the calliper to dislodge any bubbles, and got the brake nice and low so any bubbles should rise easily. Finally I tried cracking open the banjo on the master cylinder while giving it a pump, and after a couple of goes I’ve got a pedal of sorts. I haven’t yet reassembled it to running order but I think I’ll have an operational brake, but with a lot of travel. Not ideal.

What sort of engineer designed such a crap system? The banjo is such an obvious air trap yet it has no proper means of bleeding. Does anyone know if there is a bleedable banjo bolt available that is low-profile enough to clear the air Box? (The bike’s a 2014 Evo 2T, btw.)

Rant over. I shall now go back to the Christmas sherry and nuts.

[kurtas]

You should try cracking the banjo while holding pressure on the rear brake, quite often shifts the stubborn air.

[fantic240motor]

Have you tried pushing the pistons right back in the calliper when bleeding? 

[Bm1200]

Hi there

I found the best trick with your old 4t is to take the master cylinder off the bike lower it and tilt it so the air can go straight up hill. You will need to push the piston with a screwdriver and it would be useful to have a spare hand to open and shut the bleed nipple but it does the job in about a dozen pumps.

 

Nige

[trapezeartist]

On 12/23/2019 at 4:58 AM, kurtas said:

You should try cracking the banjo while holding pressure on the rear brake, quite often shifts the stubborn air.

 

On 12/23/2019 at 5:37 PM, fantic240motor said:

Have you tried pushing the pistons right back in the calliper when bleeding? 

Yes to those, and that’s how I finally got to where I am now. The bike is back together and the brake feels just about OK. A trial in the next few days will confirm or not. But what a crazy idea to just loosen a banjo bolt instead of having a proper bleed nipple. All it would require from Beta would be a small mod to the air box and the use of a banjo bolt with nipple.

[trapezeartist]

13 hours ago, Bm1200 said:

Hi there

I found the best trick with your old 4t is to take the master cylinder off the bike lower it and tilt it so the air can go straight up hill. You will need to push the piston with a screwdriver and it would be useful to have a spare hand to open and shut the bleed nipple but it does the job in about a dozen pumps.

 

Nige

Hi Nige

I should never have sold that bike.?

I thought about doing it your way but didn’t have an assistant to provide the extra hands. Also tilting the master cylinder would make it awkward to maintain the fluid level without another assistant squinting in fluid from a syringe. Do you put the cap back on when doing it? I thought about getting another cap, drilling it and putting in a fill tube with araldite. Then pressure filling it like that.