[Blapper]

Hi everybody. I have two questions for you. Firstly; my brakes are due a fluid change - do I need any special tools or procedures to bleed the brakes on my 2014 GT?
Second question; after my bike sat on my Optimate over this winter, the brake lever came straight back effortlessly to the handle bar. I started the engine and normal service was resumed. I've never had that happen on this bike before, can anybody explain why it happened?
TIA.

 

[Richard230]

While I don't own a GT, I did recently replace the brake fluid on my R1200RS, KTM Duke and Zero electric motorcycle. All three of those bikes have ABS, which I just ignored and changed the fluid just like you would do back in the dark ages. The brake fluid changes went normally and the brakes work just as well as they did before the change - other than the fluid is now clear instead of a light brown.

Regarding your other question: I have no idea what is going on with that. If your bike was 20 years old and had BMW's "here today, gone tomorrow", power brakes, that might be typical, but with the GT, which has a normal brake system, I don't know what to say.

 

[Redned]

Blapper. Agree with Richard230. Bleed as with any hydaulic system (car or Bike). There are a number of gadgets/tools on the market that make the job "easier", but in my experience, unless the job proves to be particularly stubbon you should be fine without them. If your bike is fitted with ABS and you have access to a GS-911 or Motoscan, flushing the ABS circuit doesn't hurt, but as Richard says is not absolutely necessary.

 

[Blapper]

Hi guys, Thanks for your input. I am very used to building and restoring bikes, but not with abs which is why I'm asking about the unexplained total loss of lever pressure and if there would be any difficulty changing the fluid.
Redned you mention the GS-911 gadget - I have heard of it but don't have one and will shortly be selling the bike so it isn't worth buying one. If I bleed the system thoroughly does all the fluid get changed or would there be some left in the abs system or whatever?

 

[Richard230]

If you bleed the brake lines normally, the fluid in the ABS pump will not be affected. But then it probably is not contaminated anyway. BTW, if you are bleeding brakes by yourself, I highly recommend using a vacuum pump, like the Mighty Vac, to suck the old fluid out of the system. It works really well. Much better than those cheap one-way valves sold on Amazon.

 

[Blapper]

Hi Richard. I do have a vacuum setup but don't use it as I find it likes to suck air past the bleed screw which makes you think you are still getting air out - two bottles of fluid later, still happening. I find the expensive Stahlbus auto bleed valves far better and they make it a one person job.
I am very interested by you saying that the fluid in the abs circuit probably isn't contaminated. As far as I know, the BMW dealers have a widget which somehow enables that to be changed at the same time as the rest of it.

 

[Richard230]

Hi Richard. I do have a vacuum setup but don't use it as I find it likes to suck air past the bleed screw which makes you think you are still getting air out - two bottles of fluid later, still happening. I find the expensive Stahlbus auto bleed valves far better and they make it a one person job.
I am very interested by you saying that the fluid in the abs circuit probably isn't contaminated. As far as I know, the BMW dealers have a widget which somehow enables that to be changed at the same time as the rest of it.

Yes they do. That is why it takes an hour or so of shop time to change the brake fluid on a ABS system. But I don't see how the fluid in an ABS pump can become contaminated. So I am not too worried about that happening - especially as I have never had the ABS activate on any of my motorcycles. The old BMW ABS systems had several bleed valves that you needed to cycle to make sure that you had all of the air out of the pump. But I don't think the new versions need to be bled that way any longer. Does anyone know differently?

 

[MGD109]

.............. I do have a vacuum setup but don't use it as I find it likes to suck air past the bleed screw which makes you think you are still getting air out - two bottles of fluid later, still happening.

I found the same, but an application of grease on the bleed screw threads stopped air being sucked in past them.

I am very interested by you saying that the fluid in the abs circuit probably isn't contaminated. As far as I know, the BMW dealers have a widget which somehow enables that to be changed at the same time as the rest of it.

MotoScan App (and I assume GS-911) have the function to bleed the ABS module. The official line is that unless air has some how got into the ABS module then it's not needed. However others like to go through the process because, if like Richard you never have the ABS come into play on the road, it activates the various valves in the ABS module and at least prove they still function.

 

[Blapper]

Ok, thanks, that seals it - I will have to pay the ridiculous prices the dealer charges to service my bike then. I have no air in my system, I am only bleeding it to get rid of absorbed moisture. I imagine that leaving such fluid in the abs circuit will quickly contaminate the fresh. Old brake fluid goes quite gelatinous so I suspect it was something like that which caused the brake pressure to disappear over winter.

 

[BoxerBits]

Blapper

Sound advice from MGD in my opinion.

FWIW the Motoscan App and the required connector would set you back less than an hour's labour at Motorrad Franchise. It can also be used on the more modern Boxers.

If the expense is the issue, then a few members of this and other BMW forums have one so you could potentially borrow (beer voucher exchange) one or even loan from the owners club.

 

[Blapper]

Ok, thanks, that seals it - I will have to pay the ridiculous prices the dealer charges to service my bike then. I have no air in my system, I am only bleeding it to get rid of absorbed moisture. I imagine that leaving such fluid in the abs circuit will quickly contaminate the fresh. Old brake fluid goes quite gelatinous so I suspe

Blapper

Sound advice from MGD in my opinion.

FWIW the Motoscan App and the required connector would set you back less than an hour's labour at Motorrad Franchise. It can also be used on the more modern Boxers.

If the expense is the issue, then a few members of this and other BMW forums have one so you could potentially borrow (beer voucher exchange) one or even loan from the owners club.

Thanks Boxerbits. To be honest, I don't even know where to find the connector! When I bought the bike, I noted that Fowler's hadn't changed the fluid and it was like honey. I challenged them on it, and they fessed up and said I should get Bahnstormer to do it as my local BMW dealer. Bahnstormer did it and said it had probably never been changed! That being the case, the fluid in the abs pump could be gelatinous like that in the reservoir was so maybe that would explain the loss of brake pressure over winter. I'm bothered this could cost me dearly thanks to previous owner/Fowlers.
When my airhead restoration is finished I will be selling the GT and going back to a bike I can fully service in an hour and a half with no widgets!

 

[BoxerBits]

Understand Blapper, having said that I always found replacing the hinged oil filter on Airheads with Rt or Rs fairings a messy task. Not to mention the hot exhaust down pipe ready and waiting to burn your knuckles. Just thank yourself for not buying a 1150 boxer with servo brakes

Connector on the F8GT is on off side under seat not far from petrol filler. There are a few threads on the forum about this and the Motoscan which are worth reading. (MGD and Bogbody have posted several)

Worth the small expense in my view.

 

[N4HHE]

Ok, thanks, that seals it - I will have to pay the ridiculous prices the dealer charges to service my bike then. I have no air in my system, I am only bleeding it to get rid of absorbed moisture. I imagine that leaving such fluid in the abs circuit will quickly contaminate the fresh. Old brake fluid goes quite gelatinous so I suspe

When you flush the brakes you are not perfectly washing the walls of the tubing or the master cylinder or the brake calipers. You worry too much about the fluid in dead-end passages of the ABS. This fluid will migrate with the new fluid. Yeah, "contaminate the new fluid". But that is happening anyway. The only issue is if solids accumulate in the dead end passages.

This is also why some advocate first brake fluid flush at 4 years, then every 2 years thereafter. The flush is not a perfect clean-out, and the new brake system started clean.

To deal with the ABS just flush your fluid then go for a ride and do your best to lock the brakes. Let the ABS pump. Then if anal flush your brake fluid again. Or not.

Some advocate testing brake fluid for water and only flushing if contaminated. The only problem with this is the test kit is expensive. My labor to change my own brake fluid is cheaper. But what I would charge you probably isn't.

 

[Blapper]

When you flush the brakes you are not perfectly washing the walls of the tubing or the master cylinder or the brake calipers. You worry too much about the fluid in dead-end passages of the ABS. This fluid will migrate with the new fluid. Yeah, "contaminate the new fluid". But that is happening anyway. The only issue is if solids accumulate in the dead end passages.

This is also why some advocate first brake fluid flush at 4 years, then every 2 years thereafter. The flush is not a perfect clean-out, and the new brake system started clean.

To deal with the ABS just flush your fluid then go for a ride and do your best to lock the brakes. Let the ABS pump. Then if anal flush your brake fluid again. Or not.

Some advocate testing brake fluid for water and only flushing if contaminated. The only problem with this is the test kit is expensive. My labor to change my own brake fluid is cheaper. But what I would charge you probably isn't.

Hi N4HHE,
Yes, it is solidification of the stagnant fluid that concerns me.
I think I will activate the abs next time I ride. It only requires firm front brake and too much rear.
👍

 

[Blapper]

Understand Blapper, having said that I always found replacing the hinged oil filter on Airheads with Rt or Rs fairings a messy task. Not to mention the hot exhaust down pipe ready and waiting to burn your knuckles. Just thank yourself for not buying a 1150 boxer with servo brakes

Connector on the F8GT is on off side under seat not far from petrol filler. There are a few threads on the forum about this and the Motoscan which are worth reading. (MGD and Bogbody have posted several)

Worth the small expense in my view.

Thankyou BoxerBits, that's very helpfull.

 

[bubble]

for last 50 years i have used a bit of rubber hose with one end on the bleed nipple and the other in a jar with some brake fluid in, pumping the brake till all the air is out can i still do this on my GT, erm not same bit of hose for the last 50years

 

[N4HHE]

for last 50 years i have used a bit of rubber hose with one end on the bleed nipple and the other in a jar with some brake fluid in, pumping the brake till all the air is out can i still do this on my GT, erm not same bit of hose for the last 50years

I usually use cheap clear vinyl hose than I can discard after use rather than try to keep clean until next use. Often gets hard due to brake fluid before next use. Also clear to see bubbles.

Past 10 years I have used a $30 Harbor Freight air powered bleeder tool. Must be careful because it can suck a motorcycle brake system dry in seconds. It has the advantage over pumping brake levers or weak Mity-Vac in that once fluid starts moving it doesn’t have to stop. When fluid stops bubbles have the opportunity to rise back to where they were.

 

[Crustyapo]

Hi N4HHE, Yes, it is solidification of the stagnant fluid that concerns me. I think I will activate the abs next time I ride.

You mean like this ?

 

[Blapper]

Exactly like that Crustyapo.

 

[Crustyapo]

Exactly like that Crustyapo.

That bike had been sitting since '15.