Rear Brake not working properly after puncture repair

[100WattWarlock]

Newbie question. 1150 GS 2001 ABS (not servo)
I recently got a puncture on my rear tyre fixed at a local East end bike garage, the mech used to work on Beamers, so I guessed I was in good hands, he fixed the rear, and remounted the wheel, but after a short ride, i.e. to the end of the car park, the back brake just didn't feel right, it almost felt like it was locking up, rather than releasing. And was hissing before it locked.
He checked the sensor and said there was enough room, and I watched him take the calipers off and put them back on, and he didn't do anything untoward. He said it should be fine, so the other night I'm riding home, put a bit too much pressure on the back and she locks, and starts to slide (it's dry!) managed to get her back underneath me again, but now I'm worried, any ideas??
Ta.

Thanks to Steve over at Horizons Unlimited for telling me about this site!

 

[swebb]

Newbie question. 1150 GS 2001 ABS (not servo)

she locks, and starts to slide (it's dry!) managed to get her back underneath me again, but now I'm worried, any ideas??
Ta.

My first concern would be that you supposedly have ABS, so why are you sliding anyway?????

I would take it to a BMW garage and get that checked out smartish, i'm sure as part of that process the brakes will come back "spot on"

(sorry i can't be more use with advice of what to try yourself, but i'm no mechanic, and brakes are a primary safety issue!!)

good luck, keep us posted on what the problem was!!

 

[Flying banana]

FWIW, my suggestion is that the first point to check is that the air gap for the abs sensor is correct, I think its about 4.5 millimetres, or thereabouts. From what you describe, it sounds as if teh abs is not doing what it should, in respect of releasing the brakes when the wheel locks.

There are others on here who will probably know more than me, but HTH

Phil

 

[100WattWarlock]

Yeah that's what I think it might be as well, I checked the Haynes manual, but they seem a bit sparse on info, mind you it was late when I read it!
I'm no mech, new to all this motorised 2 wheel thing really, but one thing I noticed in the Haynes manual, is that they happily unscrew the tops of the brake/clutch fluid canisters, and top up, then replace, but I thought this was not the thing to do, as air is released into the system, meaning no brakes! And BMW, said oh no don't do that you need a special XYZ pump that only we have!!?

As you can tell, I really no "nothin' mista faulty!" when it comes to Bikes, I just love 'em!
Anyone care to help me on that one as well?
I will check the distance of the ABS sensor tomorrow, but I feel a trip to BMW Battersea coming on :-(

Bloody punctures!

 

[boxer]

ABS gap should be .45mm to .55mm.

Check the tool tray under the seat there could be a set of feelers for checking this gap, though it sounds like you may be best getting more expert help.

Russ.

 

[finglonga]

Have you checked the allen bolts are tight and and every thing is in the correct position?
From your description it sounds as if the brake is locking with light pressure on the pedal. That shouldn't happen even if the ABS is turned off.

 

[100WattWarlock]

Hhhm, just went out (couldn't wait 'til tomorrow) and checked it all over, it does indeed seem as though the brake is locking with light pressure, ABS signals everything fine (go figure!) anyway lossened and resat the whole calpier, didn't check the distance, this I wil do tomorrow, but the even just riding up down the small car park area the brakes are locking, and laying rubber (bugger!) Haynes mentions a paint dot for alignement, assuming that the wheel has not been set back to it's proper position, I assume it (the sensor) will need re-aligining. Frustration can only begin to describe how i feel! Especially as tomorrow is supposed to be good biking weather.
Anyway, thanks to all who replied so far, I'll keep you all posted.

 

[boxer]

As far as I konw the abs system does not work below a certain speed - could it be that you're not exceeding this speed in the carpark.

Does the wheel spin freely with the bike on it's centerstand? Is the pedal returning to it's rest position ok?

Seems possible something simply hasn't been reassembled correctly.

I think you may find the paint dot refers to the abs ring.

 

[Den]

I dont know about the rest of you, but I hardly use the back brake at all. In fact, I can remember the exact last time I used it. At the bottom of Broom road last saturday
.
Even if the abs sensor is wonky, and assuming that the caliper is all ok, you might be pressing it too hard normally. Your abs, when working, could be activating every time you use the brake !
Alternatively, if the sliding pins are faulty, your caliper might be twisting on them and locking. Cant think of any other reason.
Wait a minute, I can. If the pads were worn unevenly, ie , like a wedge of cheese,for the want of a better description, and they were put in the opposite way, they might tend to lock on.

 

[Steptoe]

Haynes mentions a paint dot for alignement, assuming that the wheel has not been set back to it's proper position, I assume it (the sensor) will need re-aligining.

i dont want to appear rude - but going by the above post, and the others, it seems like you don't really know what you're doing -

You can lock the rear wheel up with ABS at slow speeds, otherwise you'd never stop at all -

Take it for a short ride without using the rear brake at all -

stop and feel the rear disc - is it hot, it shouldn't be -

if it is, post back and we'll take it fron there .

if you don't know about brake systems ( and you sound 100% as if you don't) leave it alone -

 

[Steptoe]

If the pads were worn unevenly, ie , like a wedge of cheese,for the want of a better description, and they were put in the opposite way, they might tend to lock on.

Com'on Den, you know better than that -

You can only put the rear pads in one way

 

[Den]

Ive never looked at them Steppie, Never used - never worn.
I bow to your superior knowledge, but a similar incident happened when I put worn pads the wrong, or opposite way in a car.
Couldnt understand why wheel was locking until I swapped pads round again.


EDIT .. Yer right, me old flower,just went out for a looksee...... silly me

By the way Neil, are you still doing front pads, mine are aboot doon tae the metal.
BMw badged capilers.

 

[100WattWarlock]

Thanks Steptoe, your name was mentioned to me over on the HU site, so thanks for replying, although I don't think your being rude, and relish your advice, I have to say that unless I learn from you lot, (which I'm doing) I will forever remain a mechanical pleb.
I don't know much about mechanics that I'll freely admit, but I rely on my senses quite a bit, and have never felt the bike react like this, but I will heed you advice, and take her for a short run tomorrow, and then let you all know what the deal is.

On another note, are there any East london riders out there who are up for the odd rideout (preferably weekends)? Assuming I can get my bike fixed!

 

[100WattWarlock]

Update

Well thanks to all for your help, I dropped the bike into BMW today, and it seems that the spacers on the ABS were missing! Wierd as I watched the mech change the back tyre, and didn't notice anything fall off when he took the rear caliper off, either way, it's fixed, and she feels "proper" again.

They also did a recall on the fuel lines and some other minor stuff.