non abs brakes

[riceburner]

Anyone got any experience with setting up the R1150R brake systems - non-ABS version??

My Rockster currently has NO brakes - I simply can't seem to bleed out a massive softness in the system.

The system on the bike is a bit messed around with- 2nd hand callipers (Tokico - like the OEs) and master-cylinder, and non-standard braided hoses (Goodridge).

The callipers were rebuilt with new seals all-round (including the internals) about a year or so ago, and I've also replaced the piston in the m/c at least once, and instead of having 1 hose to the left calliper and a loop over - the hoses are setup in "race-fashion" with a double banjo at the m/c and a long hose down to each calliper.

The m/c is 2nd had because one of the reservoir screws stripped the thread in the lug.

I have a nasty feeling that I'm trying to use an ABS m/c not one specced for non-ABS, and I think this might be why it won't bleed up correctly.

Has anyone else had any experience with accidentally (or deliberately?) setting up the brakes like this? ie non abs but with a ABS m/c? Did you have any trouble getting the brakes bled?

Alternatively, does anyone know what the difference is between the two m/cs that are specced?
ABS: 32727665864
non-ABS: 32727657182

[sweatmark]

My Rockster currently has NO brakes - I simply can't seem to bleed out a massive softness in the system.

The system on the bike is a bit messed around with- 2nd hand callipers (Tokico - like the OEs) and master-cylinder, and non-standard braided hoses (Goodridge).

The callipers were rebuilt with new seals all-round (including the internals) about a year or so ago, and I've also replaced the piston in the m/c at least once, and instead of having 1 hose to the left calliper and a loop over - the hoses are setup in "race-fashion" with a double banjo at the m/c and a long hose down to each calliper.

The m/c is 2nd had because one of the reservoir screws stripped the thread in the lug.

I have a nasty feeling that I'm trying to use an ABS m/c not one specced for non-ABS, and I think this might be why it won't bleed up correctly.

Has anyone else had any experience with accidentally (or deliberately?) setting up the brakes like this? ie non abs but with a ABS m/c? Did you have any trouble getting the brakes bled?

Alternatively, does anyone know what the difference is between the two m/cs that are specced?
ABS: 32727665864
non-ABS: 32727657182

My assumption is that the only difference between those front brake master assemblies is in brake switches, thus accounting for the iABS versus non-ABS versions. Note that the rebuild kit is one and same for both versions.

Compare the front brake master with the rear/foot brake master. For the rear, there are two distinct versions, ABS and non-ABS, that differ in piston diameter. I considered this when un-ABS-ing my bike, but have found the rear wheel braking satisfactory post-ectomy.

I remember your comments a few years ago about the superbike brake line kit, which should be simpler to bleed than the OE circuit. What about the double banjo bolt - any chance of leaking there?


And remember some time ago when someone had some bit of dirt in the brake master causing problem? IIRC it was something plugging the smaller bleed hole. Might have been clutch side instead...

Looks like we had this conversation previously:
http://r1150r.org/board/viewtopic.php?f=3&t=18651
How did you get the front brake working at that time?

[riceburner]

From that time to this, I've had poo front brakes.

I can't quite remember how, but I managed to get them to a "usable" state, and have ridden with them like that ever since. I swear the problems all started with the 2nd hand m/c. The brakes have never been good with it.

I am currently about 3 weeks from a bike trip to France that I've been looking forward to for months, so currently I'm quite prepared to spend 250 on a OE BMW m/c just to be absolutely sure I've got the right part.

I'm going to replaced all the crush washers as well (will have to anyway, I've never re-used them).

[CycleRob]

After working 10 years in a shop environment, you create/learn the best-easy-way to do things. Not the quick-n-dirty way. The best-easy-way. The mistake everybody makes is that they try to push the air bubbles down-n-out the caliper's bleeder. The relatively slow fluid movement as you bleed the brakes means the air wants to stay in the banjo bolt pocket where it is -or- slowly float upward again between bleeding strokes. I've changed stock rubber to cool colored SS brake lines on SportBikes many times without any need to bleed the brakes - - IF the fluid is clean and new at the start. A full, hard lever in just a few minutes. No wasted brake fluid. Non ABS brakes can be bled with only ONE loosen-squeeze-tighten bleeder operation -after- using a common sense caliper piston push back, repeated many times. That pushes any trapped air up-n-out the (correctly oriented!) master cylinder. I say correctly oriented so the air bubble does not have to go downward on it's trip to the master cylinder. Do whatever you have to do, including removing and remounting the master cylinder so the piston bore opening is the highest point.For the calipers, orient them so the banjo bolt is at the highest point when you push in the caliper pistons.

This air purge is possible because the simultaneous push back of the 1, 2, or 4 pistons creates a speedy flow rate - - - back into the (covered) master cylinder reservoir. That fast flow rate takes with it any/all air bubbles in the caliper/lines/banjos up-n-out the tiny bleed back hole on the floor of the master cylinder. Using the lever/pedal to extend the pistons again onto the pads or a spacer allows you to repeat the push-back air purge operation until ALL the air is gone. This technique works even if the system is totally empty, although a MityVac hand vacuum pump bleeder speeds it up. Without one, it just takes a little longer for the additional pump-up, push-back repetitions.

If that does not fix the lever spongyness, there is a damaged or mis-installed piston rubber.

BTW, where is Hiding in your blind spot.... ?

[riceburner]

Hi Rob,

I tried a variant of the "push-back" method yesterday - using a large syringe to push fluid back up from the calliper bleed nipple to the master-cylinder. Pushed the fluid through with enough pressure to accidentally spray the garage roof with fluid.

I'm pretty sure that the calliper pistons seals are relatively ok, the brakes were "working" Friday, (as well as they have since I fitted the 2nd hand m/c) , all pistons moving freely - surely if there was a mis-installed piston seal the piston would jam? But after I changed the pads I made the mistake of trying to do a quick bleed and the system just will not stiffen up now.

The m/c is quite definitely the highest point on the circuit and always has been.

The callipers were split and rebuilt last year, all seals replaced, including the internal ones, and the brakes worked fine.

With this m/c there is a distinct amount of movement of the piston BEFORE any pressure is built up. I've observed the movement of the piston through the larger of the two holes in the m/c and observed that there is "considerable" (relatively speaking) movement before the piston seal passes the hole and starts to actually do any compressive work. I believe that this is the main issue with my brakes currently, and is why I'm going to buy an OE, confirmed NON-ABS m/c direct from BMW.

The odd thing is, that I can rationalise there being a difference between the two m/c's. My logic is that the ABS/servo system needs to be "armed & live" before there is any pressure within the brake system, so that the pressure sensors can measure the desired brake pressure before activating the servo motors to supply that pressure. It makes sense that the ABS m/c would allow a small amount of brake lever movement before any pressure is built up - so that the micro-switch in the assembly is ensured to have been activated BEFORE the hydraulic pressure builds up. I'll admit I've not ridden an iABS equipped bike for a while, but when I did, I do remember that the brakes, while powerful, were NOT immediately activated when you squeezed the lever, I was unable to "graze" the brakes gently - they were either off, or very definitely ON.

[grwrockster]

RB - I've been away in Cornwall for the last week, and away from WiFi, email etc. (made a nice change!).

Anyway - I realise you may have a new m/cyl now and/or have solved the problem. And -I wouldn't rdeam of second-guessing CycleRob's sage advice (which you've tried already).

But, just in case and cos it'll cost you nothing to try...... have you tried the old trick of tying the brake lever under pressure to the twistgrip (with the brake reservoir cover loose) and leaving it overnight to allow any stubborn small air bubble time to bleed out to the surface?

My front brake has always felt slightly more spongy (non-ABS) since I replaced all the fluid, so I did this myself a couple of weeks ago when I was changing tyres. The lever is definitely firmer and the brakes a bit sharper after leaving it like this for 24-hrs (Note I had the wheel off, so put strips of stick on wheel-balance weights in between the brake pads in lieu of the discs - this meant that the lever came back to the 'bar when taking up the slack and the pads gripping the wheel-weight strips).

With the lever tied off, I left the master cylinder cover resting with a gap to allow air into the top, and put a clean dry cloth over that to try and minimise the brake fluid from absorbing moisture from the air. Then I just left it like that until I was ready to put the wheel back on.

[Sunbeemer]

This may or may not be true, but I've heard and read (more than once) that when bleeding brakes by pumping the fluid through the caliper bleeder screw with the brake lever, the brake lever should not be pulled all the back to the handlebar, which (apparently) runs the lip of the master cylinder's piston seal past the end of the cylinder bore which damages it.

It's "believe it or don't", but since it doesnt hurt to not do it, I avoid doing it.

[riceburner]

RB - I've been away in Cornwall for the last week, and away from WiFi, email etc. (made a nice change!).

Anyway - I realise you may have a new m/cyl now and/or have solved the problem. And -I wouldn't rdeam of second-guessing CycleRob's sage advice (which you've tried already).

But, just in case and cos it'll cost you nothing to try...... have you tried the old trick of tying the brake lever under pressure to the twistgrip (with the brake reservoir cover loose) and leaving it overnight to allow any stubborn small air bubble time to bleed out to the surface?

My front brake has always felt slightly more spongy (non-ABS) since I replaced all the fluid, so I did this myself a couple of weeks ago when I was changing tyres. The lever is definitely firmer and the brakes a bit sharper after leaving it like this for 24-hrs (Note I had the wheel off, so put strips of stick on wheel-balance weights in between the brake pads in lieu of the discs - this meant that the lever came back to the 'bar when taking up the slack and the pads gripping the wheel-weight strips).

With the lever tied off, I left the master cylinder cover resting with a gap to allow air into the top, and put a clean dry cloth over that to try and minimise the brake fluid from absorbing moisture from the air. Then I just left it like that until I was ready to put the wheel back on.

Lever is currently tied back - will check it tonight. I'm not too worried about the "furthest point of movement" damaging the new piston seal, the m/c is all new now so should be ok.

My next step is to test each calliper in isolation (ie find a single banjo bolt for the m/c and see if I can bleed up each calliper successfully, one at a time). If it appears that just one of the callipers is the problem I'll rebuild it (again!)

[riceburner]

Thanks for all the suggestions & advice.

I've cracked 'em

Someone on my other forum suggested that if the weather seals were full of crud they would be prevented from advancing properly and thus you'd never get any proper pressure build up. Thought about it and the logic seemed correct. So i popped each piston individually, stripped out the weather seals, which were ALL full of white gack & dust. And as I progressed the pressure came back into the system! Brakes are now brilliant!

For the future I'm going to look into fitting either the Brembo callipers that were the alternative factory fitting, or potentially a pair of Nissins.

[riceburner]

Baah - and it continues!

Although I had useable brakes when I left for my weekend in France, they're now back to "soft as a very soft thing". Weirdly there isn't even decent pressure when the bike is stationary - you can't pump the system up.

I had thought that maybe while the bike was moving, if the discs were slightly warped, they might have been batting the pistons back slightly, but although they've got 16,000 miles on, they seem to be in good nick.

My only conclusion is that there "must" be some air getting in somehow - but I'm confused as to how this can happen without some fluid getting out.

[grwrockster]

RB - did you actually fit a new m/c then?

If you didn't then surely now that is the place to go looking? I'm not expert for sure, but I'd be looking at the m/c, as without fluid leaks evident, and being unable to build up pressure (which even with a bit of air in the system should still occur), then it seems like the natural point to go looking?

If you HAVE fitted a new m/c, then it's one to make one for sure!

I have a non-ABS bike (std Rockster set-up with braided lines) as you know, and I replaced the fluid earlier this year without any problems (mind you - all I did was continuously bleed fresh fluid through the system to expel & replace the old stuff with no disassembly of the primary components) - and I've not suffered the hassles you've had.

Do you know anyone local with a non-ABS bike who'd be willing to let you 'try' their m/c on your system before you start spending more on bits?

I've been lucky in all my biking 30-odd years and never had to repair/replace a m/c or brake caliper - std mtce of simply cleaning and bleeding has always done the trick for me (so far). Have done a m/c on a car donkey's years ago, but that's all. If you've done CycleRob's routine and that's not worked, then it seems that systematic swapping out of bits to try and work through the problem is in your future?

I wish you luck!

[riceburner]

RB - did you actually fit a new m/c then?

Yup - £270 worth....

If you didn't then surely now that is the place to go looking? I'm not expert for sure, but I'd be looking at the m/c, as without fluid leaks evident, and being unable to build up pressure (which even with a bit of air in the system should still occur), then it seems like the natural point to go looking?

If you HAVE fitted a new m/c, then it's one to make one for sure!

I have a non-ABS bike (std Rockster set-up with braided lines) as you know, and I replaced the fluid earlier this year without any problems (mind you - all I did was continuously bleed fresh fluid through the system to expel & replace the old stuff with no disassembly of the primary components) - and I've not suffered the hassles you've had.

Do you know anyone local with a non-ABS bike who'd be willing to let you 'try' their m/c on your system before you start spending more on bits?

I've been lucky in all my biking 30-odd years and never had to repair/replace a m/c or brake caliper - std mtce of simply cleaning and bleeding has always done the trick for me (so far). Have done a m/c on a car donkey's years ago, but that's all. If you've done CycleRob's routine and that's not worked, then it seems that systematic swapping out of bits to try and work through the problem is in your future?

I wish you luck!

My next "venture" is more than likely to be attempting to fit some Brembo calipers instead of the Tokicos. It was suggested on TRC that I try Nissins, but I know that the BMW EVO system uses Brembos as well as Tokicos (seemingly randomly), so I should be able to pick up some 2nd hand Brembos from Motorworks et al (with any luck) which will be BMW specific.


Haven't had a chance yet to start looking though.