brake problem

[KenG]

came in yesterday and was doing a 9+ point turn to get turned round as i reverse the bike into the shed.
moving forward on full left lock at 0.25mph, i dabbed the front brake lever, but it wouldn't release.
then i wiggled the bars and it came off.
tried it again and it's only happening to the left lock, had a quick look and can't see any pipes catching, cracked, or frayed.

first thing i'm thinking is an original flexi-hose has collapsed inside, showing no external damage. and it's holding the pressure on until the handle bar is returned to centre.

also noticed on run that the brakes were a bit snatchy,but i thought it was wet pads from washing and putting away without riding it, but that would have cleared in first mile or two. but it was like it all day.

do you think i'm in the right area for investigation?, what next?
or anything else that i'm missing??

[cornishflat]

Very strange. Given the age of bike new hoses would be a good start and as a bonus you will probably improve the braking too. I,d go with two individual hoses from the likes of HEL who can custom make a set for £40 - £50.

[dave the german]

Cornishflat, you recommend 2 hoses from the master cylinder and not the link pipe? just askin cos I'm probably going to the NEC and HEL usually have some show offers on so looking to get pipes for the BCR and my long term SR500 project. Next question have you got them fitted this way and how long is the pipe to the N/S caliper?

[Corvus]

came in yesterday and was doing a 9+ point turn to get turned round as i reverse the bike into the shed.
moving forward on full left lock at 0.25mph, i dabbed the front brake lever, but it wouldn't release.
then i wiggled the bars and it came off.
tried it again and it's only happening to the left lock, had a quick look and can't see any pipes catching, cracked, or frayed.

first thing i'm thinking is an original flexi-hose has collapsed inside, showing no external damage. and it's holding the pressure on until the handle bar is returned to centre.

also noticed on run that the brakes were a bit snatchy,but i thought it was wet pads from washing and putting away without riding it, but that would have cleared in first mile or two. but it was like it all day.

do you think i'm in the right area for investigation?, what next?
or anything else that i'm missing??

Is it a case that the lever is not returning, or is it returning (maybe a tad slowly) but the brakes are holding?

To my way of thinking you could have hydraulic related issues at either the master cyl or caliper cyl. Most likely in my book is the caliper end.

Perhaps the issue is not "hydraulic" ie not related to either cylinders or hoses, although it most likely is.

[cornishflat]

Cornishflat, you recommend 2 hoses from the master cylinder and not the link pipe? just askin cos I'm probably going to the NEC and HEL usually have some show offers on so looking to get pipes for the BCR and my long term SR500 project. Next question have you got them fitted this way and how long is the pipe to the N/S caliper?

Hi Corvus, I went with two separate hoses as it was easy and was recommended on here, also everything is new from top to bottom. I have Barbacks fitted so the hoses were longer than standard, I used a piece of wire and routed it as per the hose to get the length. HEL are very helpful on the phone, they asked for hose lengths and angle of the Banjo fittings, the hoses arrived in less than 48 hours. Incidentally I did the same for my R80 bobber with the same excellent service.

[cornishflat]

Sorry corvus, that reply should have read ........sorry Dave.....its early

[Corvus]

Sorry corvus, that reply should have read ........sorry Dave.....its early

I've been called worse.

[Corvus]

Cornishflat, you recommend 2 hoses from the master cylinder and not the link pipe? just askin cos I'm probably going to the NEC and HEL usually have some show offers on so looking to get pipes for the BCR and my long term SR500 project. Next question have you got them fitted this way and how long is the pipe to the N/S caliper?

Hi Corvus, I went with two separate hoses as it was easy and was recommended on here, also everything is new from top to bottom. I have Barbacks fitted so the hoses were longer than standard, I used a piece of wire and routed it as per the hose to get the length. HEL are very helpful on the phone, they asked for hose lengths and angle of the Banjo fittings, the hoses arrived in less than 48 hours. Incidentally I did the same for my R80 bobber with the same excellent service.

I ran it that way on my fzr thou. Was a doddle to bleed. Let gravity do 99% of the work.

Looks wise, I guess that is subjective, but I prefer it and will be doing the same on my R100 in the near future.

My bro used black coated braided hoses and I have to say they do look rather good.

I would advise avoiding "cheaper" brands as I used a "cheaper" brand on my hydraulic clutch but the coating is showing UV discolouration in only 5k miles. The venhill hoses on the brake are standing up fine.

Cheers.

[KenG]

came in yesterday and was doing a 9+ point turn to get turned round as i reverse the bike into the shed.
moving forward on full left lock at 0.25mph, i dabbed the front brake lever, but it wouldn't release.
then i wiggled the bars and it came off.
tried it again and it's only happening to the left lock, had a quick look and can't see any pipes catching, cracked, or frayed.

first thing i'm thinking is an original flexi-hose has collapsed inside, showing no external damage. and it's holding the pressure on until the handle bar is returned to centre.

also noticed on run that the brakes were a bit snatchy,but i thought it was wet pads from washing and putting away without riding it, but that would have cleared in first mile or two. but it was like it all day.

do you think i'm in the right area for investigation?, what next?
or anything else that i'm missing??

Is it a case that the lever is not returning, or is it returning (maybe a tad slowly) but the brakes are holding?

To my way of thinking you could have hydraulic related issues at either the master cyl or caliper cyl. Most likely in my book is the caliper end.

Perhaps the issue is not "hydraulic" ie not related to either cylinders or hoses, although it most likely is.

lever is returning fine in every other position, which points me to the steering, maybe a hose coming of its joint at the banjo has collapsed, and is only an issue in the left position.

i'm off tomorrow and will get a look at it, i was just wondering if it had happened before to anyone.

thanks for reply's

[Droptarotter]

It is possible that a brake hose has collapsed internally. I had that happen on an old Dodge van.
You do say the lever is returning, but is the master cylinder push rod returning also?

The main reason guys go to only 2 brake lines from the master is that you are using less joints/banjo bolts. Less places to leak and easier to bleed. It's an old road race trick.

Install new brake lines and go from there......can't hurt to have fancy new lines.

Cheers

[KenG]

was googling the simple stuff, so pulled out pads and checked all cylinders were moving there at lunchtime, and copper greased the edges etc going back in.
went to give it a bleed through and lost everything, a real cock up to say the least. so google's it again to see how to bleed it, says i need a funnel and speed bleeders.
http://users.rcn.com/dehager/service/service_abs3.pdf

prob going to need to do this if i change the lines, but after checking everything, i would prefer to see how it is again on a full pressure system, before i go any further.
sitting in the yard in pieces to i get home now at 5.

[Corvus]

It is possible that a brake hose has collapsed internally. I had that happen on an old Dodge van.
You do say the lever is returning, but is the master cylinder push rod returning also?

The main reason guys go to only 2 brake lines from the master is that you are using less joints/banjo bolts. Less places to leak and easier to bleed. It's an old road race trick.

Install new brake lines and go from there......can't hurt to have fancy new lines.

Cheers

If you share the banjo on one of the calipers and loop over the mudguard surely that is the same number of joints as two going from the master cyl?Going into a splitter manifold would be more joints though.

Two lines straight down from the master cyl is definitely easier to bleed, for the home mechanic anyway. Anything which goes over in bridge fashion just has to be an air trap. Two lines going practically straight down to each caliper virtually bleed themselves.

This is nit picking and I'm not suggesting we worry about it, but how is the unsprung weight affected? How much of a brake line which goes from master cyl to caliper is actually unsprung? Any loop going over the mudguard is fully unsprung. The double banjo is fully unsprung. I don't even know if moto gp people would worry about that, but it's a thought!

[SP250]

Don't forget you will need a new double banjo bolt for the master cylinder if you go down the separate twin lines to calipers route and all new copper washers.

[KenG]

a plastic funnel out of poundland modified and screwed in here.
bottles and pipes strapped to all 3 wheel bleeders.
1lt of dot4.

what a hoore or a job.

so all calipers free'd up, greased, etc
pump bled through as per pdf above, and wheels bled into bottles.



tank and seat on for a test run


right, sitting up on the stand, all brakes operating 100%.

but still stick's on the ground, so i held it on sticking on the ground, put down the side stand and got the son to help list the wheels and turn them, and they're free.

did bmw ever put something into the suspension to stop these rolling forward of the side stand or something stupid.
caus i can't find a fault with brakes 5 hrs later. !!!!!!!



ps, if you haven't got the PDF above saved and you own a r1150rt with abs, get it saved, you might meed it one day.

[Corvus]

Well, what they saved in complexity in the engine they certainly made up for in the brake plumbing! That would have made a perfectly good space for a couple of decent sized sandwiches.

Call me a Luddite.