Brake fluid change - Servo ABS

[MOTOTECH]

i had a master cylinder changed at a bmw dealer. they told me they couldn't do the specified pressure test as there was no power in the workshop due to a storm.
they said it didn't really matter & i was ok with that. done 10000+ miles since and all is fine.

The test is just that, if the system is bled propperly, it will come up ok.
It works by going through a sequence then holding the brakes between a set pressure range for a set time.
I have the equipment to do it if required.
Brian.

 

[bozokozu]

Could Brake Bleeding be necessary after changing wheels?

Hi Guys,

I've been reading this thread in an attempt to understand my bike a bit better, and I could sure use some advise!

I have an 56 reg GSA with semi-integral ABS brakes (non-servo) and I've just had a 12K service and 2 year inspection done on at SLM, and despite £370 compared to a quoted £240, and the bashplate fell off coz' they left the bolts loose [I dread to think what else they haven't tightened!], things are good. Since the service last month I recently had a bike mechanic replace the Metzler Tourances on both wheels with Michelin Anakee 2's that I got off eBay.

I did each wheel in turn, and when I had the front off, I just unbolted the calipers from each leg and let them dangle for a few days whilst the tyre was being changed.

After I put the front wheel back on and refitted the calipers, I was very surprised to see the front brake lever had like no resistance when pulled at first. After turning on the ignition and squeezing the lever several times it is better, but I'm not sure if it's back to "normal".

I didn't put a blocks inside the pads to keep them apart, but they didn't seem to move much whilst they were off the bike. I haven't touched any of the brake lines and there is no loss off any fluid.

IS THIS NORMAL!

Does the front (and possibly the back?) now need to be bled and is this a major deal? It's still in my garage and I haven't actually started it up or ridden it yet - just in case.

Please help and I'm looking forward to your replies!

 

[patzx12]

Hi, The brakes would need pumping once you replace the wheel.
You surly would have had to push the pads back a bit to refit the calipers.
If they are working fine now all should be well.
Re service, I hate anyone else working on my bikes and I only take it to a dealer if it is in warranty.
No one loves your bike as much as you.

 

[Brian ROSEN]

Servo brakes

"..., thats why BMW have got rid of the damn things. To many failures..." i don't think think that is true. the servo brakes were excellent in every way; however from my experience on the 2008 model the new (updated?) system without servo is just as effective;

 

[BBB61]

I've just done both the wheel and control circuits on my GS for the first time, and I was surprised at how straightforward it was. I didn't use the made up funnel as shown on ADV Rider, I just used an ordinary funnel and topped the reservior up as and when required. With the servo system, bleeding the wheel circuit is very easy as the servos do the work of pumping the brake fluid through. The only thing I didn't have for doing the control circuit was a 7mm spanner, but I managed to work round that ok.

 

[Steptoe]

i don't think think that is true. the servo brakes were excellent in every way; ;

I never said they weren't "excellent in everyway" .

It's when the servo stops working that the fun and games start, hence why BMW no longer fit them.

 

[Brian ROSEN]

Misunderstood?

I never said they weren't "excellent in everyway" .

It's when the servo stops working that the fun and games start, hence why BMW no longer fit them.

What I intended to imply was that the new 2008 non servo brakes seem (to me anyway) to be just as effective as the original servo units. I suggested that the servo was discontinued because the extra complication/expense/pssibility of things going wrong ec; could now be avided. I think we are in fact on ' the same tack.'

 

[digga]

Hi Guys,



After I put the front wheel back on and refitted the calipers, I was very surprised to see the front brake lever had like no resistance when pulled at first. After turning on the ignition and squeezing the lever several times it is better, but I'm not sure if it's back to "normal".

I didn't put a blocks inside the pads to keep them apart, but they didn't seem to move much whilst they were off the bike. I haven't touched any of the brake lines and there is no loss off any fluid.

IS THIS NORMAL!

Does the front (and possibly the back?) now need to be bled and is this a major deal? It's still in my garage and I haven't actually started it up or ridden it yet - just in case.

Please help and I'm looking forward to your replies!

Therein lies your problem i believe......

you bled all the pressure out of the servo when you squeezed the lever.. you need to run the engine to build pressure again inside the servo....

Well thats the way i read what you have typed.... try it and see

 

[ebbo]

"..., thats why BMW have got rid of the damn things. To many failures..." i don't think think that is true. the servo brakes were excellent in every way; however from my experience on the 2008 model the new (updated?) system without servo is just as effective;

Will we ever know why BMW ever fitted them? I have servo and ABS, ABS is great, servos, just a waste of time

 

[cookie]

the servo'd bikes i've ridden have had way more braking power than the later non servo models.

useful when fast and loaded, i imagine, at other times like driving an old citroen.

 

[Brian ROSEN]

Servo brakes

"....useful when fast and loaded, i imagine, at other times like driving an old citroen...." Well, I have to admit that I liked them.......but then again I did drive an old Citroen! They were useful where I live because it is very steep, very twisty and it is impossible NOT to use the brakes frequently. However as I said the new (servo-less) ones seem just as good.

 

[bozokozu]

Hi Digga, I thought my '56 reg GSA had integral but NON-SERVO brakes? I didn't think that having the engine running would make any difference to the pressure in the system. After a few squeezes on the lever (when I felt some resistance), there was a noticeable squish-noise from the resevoir up on the bars. With slow constant pressure on the lever, it will eventually get very close to the grip - so there must be air in there - and I assume it's in the front control circuit. I guess I should check the wheel circuit too!

 

[cookie]

"....useful when fast and loaded, i imagine, at other times like driving an old citroen...." Well, I have to admit that I liked them.......but then again I did drive an old Citroen! They were useful where I live because it is very steep, very twisty and it is impossible NOT to use the brakes frequently. However as I said the new (servo-less) ones seem just as good.

i'm sure most people would get used to them, i just wanted to make the point that they are considerably more powerful than the later, non servo equipment.

i too used to drive an old citroen

 

[GS7A]

Vacume bleeding with Servo and ABS?

Is there any reason why you cant simply use a vacume bleeding system rather than use the method described on Adventure rider? The Adventure rider solution looks easy enough but I would have thought that using a vacume bleeding system would do the job equily as well? Do you realy have to remove the pads and push back the pistons? I have bled hundreds of cars with ABS using a vac bleeder without any problems and have never had to remove the pads. Is this something unique to the BMW system on the GS???

 

[GSinfo]

Cheers Neil, I had hoped it would be that easy.

Any idea why the GS-911 tool can't 'read' the ECU for a brake pressure test like the BMW GT1 machine can? Surely the bikes' ABS electronics incorporates a transducer to sense braking force.

Edit: Just seen Ty's post above re GS911. Thanks Ty.

hi Pukmeister,

just to answer the above - we decided to give ALL control units the the basic functionality (ECUinfo and read/clear fault codes) before we take each of them one for one and add their service & maintenance functionality... in the latest Official release 904, (see the News release on our webpage), you will see that we've already started adding full service functionality (first one has been the ABS-N (found in all single cylinder F650 and C1)) which will steadily be followed by the others... (unfortunately only 24 hours in each day) - see our roadmap for details.

best,
Stephan

 

[Pukmeister]

Thanks Stephan. Glad to see we are keeping you busy.

 

[andy white]

Hi All,

Just finished a fluid change on a mates Servo GSA, thanks for the info People, it would have been a Fekkin nightmare without. Gotta be honest, im glad BM have decided to stop fitting it,

Servo ABS; Great when it working, Expensive pain in the ass when its not

Cheers