Lost me front brakes

[meistershite]

Hi Guys, Need a little help....Parked my 99 R1100S up 3 weeks ago, all working fine. Went to use it Sunday and the front brake lever went straight back to the bar on the first pull. If you pump it a couple of times, you get pressure up. I have since bleed the front brakes, no air came out. I have removed the calipers and checked that non of the caliper pistons are seized. I clamped the master cylinder hose, got a solid lever, thats fine. Clamped the hose on the return from the ABS pump, again a solid lever. Then clamped the caliper hoses indvidually and got a good lever. Any ideas?

[Jason M]

Hi Guys, Need a little help....Parked my 99 R1100S up 3 weeks ago, all working fine. Went to use it Sunday and the front brake lever went straight back to the bar on the first pull. If you pump it a couple of times, you get pressure up. I have since bleed the front brakes, no air came out. I have removed the calipers and checked that non of the caliper pistons are seized. I clamped the master cylinder hose, got a solid lever, thats fine. Clamped the hose on the return from the ABS pump, again a solid lever. Then clamped the caliper hoses indvidually and got a good lever. Any ideas?

Nothing I can think of, except the ABS somehow in error and thinking the wheels are locked therefore and letting the brakes off or something - I presume all the check lights are out and the same thing happens the engine running/off/bike in motion?

Jason

BTW - I thought bleeding ABS brakes was a job exclusively for BMW 'gizmology'

[meistershite]

Hi Jason,

Thats what I thought, so I took it for a quick blat round the block, pumped the front brake lever and then grabbed a handfull of lever.....ABS cut in , bike stopped! Curious.

[Jason M]

Hi Jason,

Thats what I thought, so I took it for a quick blat round the block, pumped the front brake lever and then grabbed a handfull of lever.....ABS cut in , bike stopped! Curious.

I presume you're not loosing any fluid then? Could be leaking amongst all the ABS plumbing under the tank?

Jason

[meistershite]

Hi Jason,

Looks like a little job for tomorrow night then.

Are they bleed nipples on the top of the ABS pump? I have never had the tank off and seen the actual ABS unit. It may be air trapped up at the ABS unit, and its not pushing through. I will check and see if I can bleed it at the ABS pump

I think the previous owner had a new pump fitted at arount 80k (It now has 107k on the clock)

Thanks

Rick

[PBBoxer]

The only thing I've ever had remotely like that is when a disk was badly bent... every time the whel went round i lost brakes...very nice it was too!

[boxerpan]

Hi Jason,

Looks like a little job for tomorrow night then.

Are they bleed nipples on the top of the ABS pump? I have never had the tank off and seen the actual ABS unit. It may be air trapped up at the ABS unit, and its not pushing through. I will check and see if I can bleed it at the ABS pump

Not that I would have anything to do with ABS, but I thought there was a special device for bleeding the ABS circuits because of the length and intricasies of the plumbing ?? Anyone else have any thoughts ??

[bernsmartco]

Does anyone on here know how the latest version of the ABS system actually works?
From reading the manual it suggests to me that the front lever fluid is not directly connected to the fluid in the brake line to the calliper because it says that the fluid level in the sight glass should remain constant even when the pads ware down. So there must be some valve arrangement in the ABS unit that senses the pressure of pulling the lever causing the pump on the ABS to kick in. Just had all the fluid changed in mine - pitty I did not ask at the time.

I guess that this problem is on a bike with the previous ABS system but if it works anything like the new system it would sugest that the problem is in the expensive pump area.

[nab 301]

Does anyone on here know how the latest version of the ABS system actually works?
From reading the manual it suggests to me that the front lever fluid is not directly connected to the fluid in the brake line to the calliper because it says that the fluid level in the sight glass should remain constant even when the pads ware down. So there must be some valve arrangement in the ABS unit that senses the pressure of pulling the lever causing the pump on the ABS to kick in. Just had all the fluid changed in mine - pitty I did not ask at the time.

I guess that this problem is on a bike with the previous ABS system but if it works anything like the new system it would sugest that the problem is in the expensive pump area.

Did this job myself about a year ago. you need a vacuum operated bleed tool mine is made by sealey but any hand operated vacuum pump will do
. You then need to follow the w/shop manual to the letter i'm assuming a 99 bike is non evo brakes. Basically you bleed the pressure modulator first (front brake then rear brake ) . Then you bleed the caliper circuits . The manual mentions special tools to press back the pistons blocks of timber can be substituted. Also i cant figure how ableed nipple works in the filler adaptor . I ended up removing the filler adaptor (in the r/h caliper) and replacing it with a bleed nipple.
ps Forgot to mention its a tank off job to bleed the pressure modulator.
Rgds Nigel B

[meistershite]

Hi Guys,

Thanks for your input, I will go and play tonight.

Giving this a little more thought and going back to my original posting, I think it must be caliper related. If I clamp off the return from ABS pump I get a good solid lever! If I clamp off each individual front hose I get a good lever. I will let you know my findings

Thanks guys

Rick

[meistershite]

I have now pumped the pistons out of the calipers, cleaned them up and reassembled the calipers. Bleed the front brake circuit.....no difference.

I checked the front pads, and they have worn down to 2mm, the wear limit acording to manual 1mm. I have now replaced them with a new set of EBC HH pads, problem solved!

Back on the road again.....at last.

Thanks for you input guys.

Regards

Rick :