Hey guys,

I got front calipers off an SP2 with only 4000 miles on them (they looked brand new when I got them) from a reputable motorcycle wrecker in the US. I also ordered Spiegler brake lines.

Went to install them and was going fine. Tried to suck fluid out of the right caliper with a home made vacuum bleeder and wasn't getting anywhere so I tried the left caliper. The left caliper was pulling out fluid without bubbles within 15 seconds. I then went to try the right caliper again and it kept spitting out a mixture of half air, half fluid.

I made sure the fittings on the right caliper and master cylinder were tight and tried again with no luck. All crush washers are definitely in place as well. I've gone through 500mL of brake fluid and the right caliper is still full of air so obviously there is air getting in between the master cylinder and the RHS caliper bleed nipple..

About half way through I noticed the fitting at the master cylinder on the braided line going to the RHS caliper was bent a bit but I undid the banjo bolt and corrected it. I doubt this would have punctured a hole in the line as they're quite thick and the bend wasn't that extreme (probably about a 140 degree bend)..

I really want this bike on the road in the next couple days but I don't know what I should do now..

I guess one option would be to swap the lines over (if the right line will reach the left caliper) and then pull the fluid through to see if it's the right line letting air in.

What are your opinions? Where do you think the air could be getting in from and what should I try?
I'm guessing (and hoping) it's something to do with the connections or the lines, but what are the chances it's a problem with the calipers?

Cheers

are the lines both from the master cyclinder?

if so have you fitted copper washers between each banjo, should be 3 at the M/C and 2 at each of the caliper banjos, and tightened correctly,

bleed one caliper at a time, youll end up having to reuse the fluid, thats what most people have to do when bleeding through, other wise you could use litres of the stuff getting them pressured,

never open the bleed nipple fully just a little so the pressure squeezes the air out to far open and you wont create any back pressure.

also, if & when you complete the said problems whack a cable tie around the lever over night, and bleed again, do it for the next few days and youll have some super sharp brakes!

Rick

also your not letting the level drop below the hold on the resovoir, its easily done when bleeding alone.

you might not have a problem dude, its just perseverance with bleeding its a bitch of a job, and touch wood ive never had a problem but i know people that have.

fill the res, tighen the bolts and bleed nipples and pull the brake lever a few times. Any leak should be very obvious.
It does take time and patience to bleed brakes.

Also doing it from scratch can take a while.... just keep at it.

Be glad you are not doing your rear caliper..now that is a ballache!

hmmm okay well I hope to God it's just a matter of perseverance.

The crush washers are definitely in place properly and the bolts are quite tight and I can't see or feel any fluid anywhere it shouldn't be so will try again tomorrow. I dumped most of my fluid into a bucket so can't reuse that but will buy another bottle tomorrow and keep putting that through and hopefully get this baby back on the road!

I was just worried because the left caliper was getting clear fluid through it within 15 seconds and the right one is still pulling out heaps of air.. I don't see how there could be that much air in the system when the system when the right line + caliper would only have a capacity of maybe 20-30mL?

Is the home made vacuum bleeder a good way to be doing this? I turn the vacuum on, open the bleed nipple, let it suck until the reservoir is almost empty, close the nipple, turn the vacuum off, fill up the reservoir and then repeat the process..

I've also got a syringe with plastic pipe set up if this would be a better method...

Cheers!

right on..

bleed your brakes into a jar so you can re-use the fluid..no point wasting it.

fill the res, pump the lever a bit and then get your spanner on the bleed nipple. Squeeze the lever to the bars, open the nipple (squirt) and close the nipple, then release the lever.

Pump the lever a few more times and repeat.

renewing fluid is easy, bleeding for dry is a pain in the arse.

get a friend to pump the lever for you - 3 squezzes and hold, undo nipple, tighten up again and then pump the lever. You should see the fluid dropping in the res - do not let it get to the bottom.

When you put the new lines and washers on the double banjo at the M/S end double check that the lines line up with the holes on the banjo, for example some banjo's need more than one washer between the lines for them to line up right. Bit of a long shot but theres not much else you can do wrong.

Thanks Mark.

Will give that a second look over Munky, although I'm 99% sure it's all good there. But thanks for the suggestion

Another option (although can be messy) fill the res right to the top, take the hoses off the calipers and put the ends in a jar and bleed them off the calipers. once you get fluid out of both lines connect them to the calipers and carry on bleeding in the normal way. this way you will be sure that the lines are full of fluid.
Also might be worth checking the thread on the bleed nipple to make sure that its not damaged and letting in air.

on checking that the fittings line up properly with the holes on the banjo. This can be an issue with parts from different bikes, etc.

It sounds like you've got enough fluid in the lines to stop using the vacuum bleeder and do it by hand at the lever using the method CMS suggests. Just keep at it and it should come good. If you're still having trouble using the lever, try taking the lever blade off and pushing directly on the master cylinder with a a drift/small socket extension, etc. (carefully) - you can move more fluid through this way.

Have you got any feeling at all in the lever yet? If you do, it could be worthwhile cable tying the lever to the bar over night and letting the system settle before attempting to bleed again - this works a treat to get the last few tiny bubbles of air out too.

Hang in there