2013 Brake Bleeding problem

[tpfeffer]

Today I bled the front and rear brakes on my new-to-me 2013 R1200RT. I've been bleeding brakes on BMW's for many years so what happened has me baffled.

 

I used Valvoline Dot 3 & 4 fluid from a new, unopened can. I replaced the stock bleeder nipples with Speedbleeders front and rear so it was an easy one-man flush. At no time did the fluid levels in the reservoirs get low enough to draw in air. I found no air in the existing fluid. Prior to the flush, the rear brakes were solid. I took care to not let brake fluid run down on the brake pads. Where some brake fluid accumulated on the caliper, I sprayed with Brake Cleaner.

 

Here's the dilemma. Following the bleeding, the rear brake feels mushy as if air was in the system. I cannot come close to purposefully locking up the rear brake or causing the ABS to activate.

 

Does anyone have a suggestion?

[duckbubbles]

It surely sounds like you've let some air in somehow. I'd remove the speed bleeder and try the regular method, since the rear is easy that way.

 

You may try using a syringe and "back bleeding" to an empty reservoir. I haven't had a whole lot of luck with that.

 

You may try completely emptying the system and starting fresh.

 

Just being patient and persistent will usually fix it.

 

Frank

[tpfeffer]

Thanks for your advise.

[dirtrider]

Morning Tom

 

How much fluid did you get through the rear? Did you put in as much as you bled out?

 

Just a thought-- but on the rear you did remove the rubber baffle in the fluid resiviour before adding fluid?

 

Otherwise it does sound like you somehow got air in the system.

 

You might bleed the rear again but do it without the speed bleeder & operate the rear brake pedal slowly not real fast.

 

Then, with the bike on the center stand & rear wheel off the ground, turn the key ON, then slowly spin the rear wheel with your foot (or have someone else spin it) as you apply the front brake lever. You should hear the servo come on & the rear brake lock up. Do this a couple of times THEN re-bleed the rear brake again.

[tpfeffer]

I pumped several brake fluid reservoirs of fluid through the rear brake caliper. The original fluid was quite dark and the new fluid lighter. So I felt I had purged the system of the old fluid.

 

It does sound like air crept in. Don't know how, but I will look at it again tonight.

 

A thought crossed my mine. If I inadvertantly got brake fluid on the brake pad material, would washing the pad with brake cleaner adeuately remove the fluid.

[Edgar]

I have struggled with speed bleeders on the rear brake in the past. I found that putting the stock bleeder back on worked best for me as it's an easy reach. I do like having speed bleeders on the fronts.

[z3406]

The BMW Reprom ( Digital BMW Repair Manual) calls for vacuum bleeding the system during a brake flush. A harbor freight vacuum pump works well. Without the special BMW brake tools what I do is this. I use a paper shop towel to blot the majority of the brake fluid from the reservoirs. I then use some water pump pliers on the brake pads to retract them as far as possible into the calipers. I then blot out the old fluid from the reservoir and top off with fresh fluid. Using the vacuum pump on the left front brake bleeder nipple suck fluid thru the system. When you see fresh fluid coming from the caliper move to the right front brake and do the same. MAKE SURE YOU DON'T SUCK THE RESERVOIR DRY. Then pump the brake lever to pump the calipers back out and check you have a firm lever. Then go to the back brake and do it the same way. According to the BMW service manual you do not use the master cylinders to pump the fluid thru for a brake flush but a vacuum pump to suck it out of the caliper.

[cris nitro]

Sorry to give you bad news, but if brake fluid got on your pads, I would replace them. Not sure if it was a little spot or a big one, still, brake pads do not like brake fluid.