Deleted account 210609001
Registered user
- Joined
- Mar 19, 2003
- Messages
- 29
- Reaction score
- 7
Superstar! 
Next Mechanical Question... Dragging Rear Brake
- Thread starter Deleted account 210609001
- Start date
I have just bled my rear brake on the WR and have a fresh bottle of DOT4 !
If you can limp it over we'll do it to Django Reinheardt and bacon sarnies ..
. 
Deleted account 210609001
Registered user
- Joined
- Mar 19, 2003
- Messages
- 29
- Reaction score
- 7
My "Superstar" comment was aimed at Dansin, NOT Giles!!!
I have my own bottle of DOT 4 to use up and plan to do the work in my well-lit, purpose built, fully equipped garage, rather than your shed.
And, as eny fule kno, technical mechanical operations need to be carried out to something more structured than jazz. Something that will encourage a methodical approach, a sombre mood and reflective approach. Not some bloody free-form, stream-of-consciousness style random notes that will inevitably lead to thoughts like "I know it says replace the seal and then fill with fluid but hey, Man, let's go with the flow and PUT THE FLUID IN FIRST. Dig that righteous guitar!"
No, it'll be structured music only. Maybe some early Bach cantatas, possibly some Vivaldi (that bloody mandolin concerto but this time on a mandolin not some church bells), or if flagging spirits need lifting, maybe some Souza marches.
As is traditional, the shake down run round my close upon completion of the work will be accompanied by Wagner's Ride of the Valkyrie.
Also, I'll have my friend Richard who actually knows his way round a spanner set to help. More the merrier though, and if you're free over the weekend Giles and want to pop over to add moral support, the bacon sandwiches will be on me this time.
Finally, my money is on buggering about with the existing master cylinder for a couple of weeks, fitting various bits of the repair kit over a succession of evenings, thinking each time that it's finally mended, before giving up and buying a new one.
I have my own bottle of DOT 4 to use up and plan to do the work in my well-lit, purpose built, fully equipped garage, rather than your shed.
And, as eny fule kno, technical mechanical operations need to be carried out to something more structured than jazz. Something that will encourage a methodical approach, a sombre mood and reflective approach. Not some bloody free-form, stream-of-consciousness style random notes that will inevitably lead to thoughts like "I know it says replace the seal and then fill with fluid but hey, Man, let's go with the flow and PUT THE FLUID IN FIRST. Dig that righteous guitar!"
No, it'll be structured music only. Maybe some early Bach cantatas, possibly some Vivaldi (that bloody mandolin concerto but this time on a mandolin not some church bells), or if flagging spirits need lifting, maybe some Souza marches.
As is traditional, the shake down run round my close upon completion of the work will be accompanied by Wagner's Ride of the Valkyrie.
Also, I'll have my friend Richard who actually knows his way round a spanner set to help. More the merrier though, and if you're free over the weekend Giles and want to pop over to add moral support, the bacon sandwiches will be on me this time.
Finally, my money is on buggering about with the existing master cylinder for a couple of weeks, fitting various bits of the repair kit over a succession of evenings, thinking each time that it's finally mended, before giving up and buying a new one.
Deleted account 210609001
Registered user
- Joined
- Mar 19, 2003
- Messages
- 29
- Reaction score
- 7
If it goes wrong it'll wreck your disc, pads and caliper but hopefully won't catch fire
It was smoking the other day! I can't make it any worse...
I did have a fire on my old K1200RS - rear brake got very hot and set fire to the rubber boot round the drive shaft/rear drive joint. Luckily a passing policeman used his fire extinguisher on it.
Deleted account 210609001
Registered user
- Joined
- Mar 19, 2003
- Messages
- 29
- Reaction score
- 7
It is perhaps a little darker than it started out. But hey, it's only the rear brake, it isn't that important...
Deleted account 210609001
Registered user
- Joined
- Mar 19, 2003
- Messages
- 29
- Reaction score
- 7
Temporary fix...
I have ordered the overhaul kit, though don't know when it will arrive. In the meantime, I removed the m/cyl this evening to have a look.
As predicted, the bottom of the piston was far from flush with the bottom of the white nylon bush and the circlip. The circlip was easily removed (using the multi-adjustable circlip pliers I bought years ago but can't recall actually using since).
Unfortunately, there was no way I could prise the piston out. Being recessed, there was no way to get access to it with any sort of pliers, and though a little corroded in the recess, there was no way to pull it out. jamming an appropriately-sized screwdriver in there revealed it would twist, but the inward pressure required to twist it meant there was no way of pulling at the same time. And the hole from the other end of the m/cyl is too small to poke through anything strong enough to drive out the piston.
Solution: blow the piston out with compressed air from my Aldi compressor. Two minor issues associated with this method. 1. It blew the brake fluid in the tube from the reservoir all over the garage and my helper, Richard. 2. When the piston eventually emerged, it all sprang out all of a sudden. I caught the piston, but the spring disappeared across the garage. The piston still had the pressure seal on it, but the o-ring wasn't there. Whether it was broken and flew off (never to be seen again) or whether it wasn't there in the first place must remain a mystery.
The piston was very stiff in the bush (ooh err missus!) though and probably the cause of my problems.
Next task - remove the white nylon bush. Impossible. Tried everything I could think of including wedging a couple of small Allen keys under the bush and pulling, but to no avail. Stuck tight. Trying to remove it was starting to damage the inner surface of the bush.
I resigned myself to having to cut it out and broke out the Dremel to do this. I also rediscovered an accessory pack I bought - from Lidl, naturally - which had some small cylinders for fixing emery paper to. That lead to my brainwave: why not use the Dremel to buff the inner surface of the bush to provide a smoother fit for the piston?
So, that's what I did. Very carefully, and slowly, and with plenty of testing, I eased the gap out until the piston was a tight but smooth fit in the bush.
Found an o-ring that fitted the groove on the piston, fitted, re-assembled, and re-installed the m/cyl. Then remove the m/cyl to put the rubber boot back on, and re-installed it again. Quick bleed of the brake (well, not that quick - three reservoirfuls required to get the air out) and all seems to be well.
Tomorrow's run to work should reveal whether it is sorted. When the overhaul kit arrives I will need to decide whether to strip it all down, remove the old bush, insert the new bush, re-assemble, re-install, remove to put the rubber boot on and re-re-install. Or just leave well enough alone, assuming it is working properly now.
We will see...
But it certainly seems to be a decent temporary repair method if you don't have a new bush immediately to hand and can't remove the old one.
I have ordered the overhaul kit, though don't know when it will arrive. In the meantime, I removed the m/cyl this evening to have a look.
As predicted, the bottom of the piston was far from flush with the bottom of the white nylon bush and the circlip. The circlip was easily removed (using the multi-adjustable circlip pliers I bought years ago but can't recall actually using since).
Unfortunately, there was no way I could prise the piston out. Being recessed, there was no way to get access to it with any sort of pliers, and though a little corroded in the recess, there was no way to pull it out. jamming an appropriately-sized screwdriver in there revealed it would twist, but the inward pressure required to twist it meant there was no way of pulling at the same time. And the hole from the other end of the m/cyl is too small to poke through anything strong enough to drive out the piston.
Solution: blow the piston out with compressed air from my Aldi compressor. Two minor issues associated with this method. 1. It blew the brake fluid in the tube from the reservoir all over the garage and my helper, Richard. 2. When the piston eventually emerged, it all sprang out all of a sudden. I caught the piston, but the spring disappeared across the garage. The piston still had the pressure seal on it, but the o-ring wasn't there. Whether it was broken and flew off (never to be seen again) or whether it wasn't there in the first place must remain a mystery.
The piston was very stiff in the bush (ooh err missus!) though and probably the cause of my problems.
Next task - remove the white nylon bush. Impossible. Tried everything I could think of including wedging a couple of small Allen keys under the bush and pulling, but to no avail. Stuck tight. Trying to remove it was starting to damage the inner surface of the bush.
I resigned myself to having to cut it out and broke out the Dremel to do this. I also rediscovered an accessory pack I bought - from Lidl, naturally - which had some small cylinders for fixing emery paper to. That lead to my brainwave: why not use the Dremel to buff the inner surface of the bush to provide a smoother fit for the piston?
So, that's what I did. Very carefully, and slowly, and with plenty of testing, I eased the gap out until the piston was a tight but smooth fit in the bush.
Found an o-ring that fitted the groove on the piston, fitted, re-assembled, and re-installed the m/cyl. Then remove the m/cyl to put the rubber boot back on, and re-installed it again. Quick bleed of the brake (well, not that quick - three reservoirfuls required to get the air out) and all seems to be well.
Tomorrow's run to work should reveal whether it is sorted. When the overhaul kit arrives I will need to decide whether to strip it all down, remove the old bush, insert the new bush, re-assemble, re-install, remove to put the rubber boot on and re-re-install. Or just leave well enough alone, assuming it is working properly now.
We will see...
But it certainly seems to be a decent temporary repair method if you don't have a new bush immediately to hand and can't remove the old one.
Deleted account 210609001
Registered user
- Joined
- Mar 19, 2003
- Messages
- 29
- Reaction score
- 7
And the good news is.....
...everything seems to be working as planned and designed. Effective rear brake, no dragging, no overheating, no sticking piston.
I impress myself sometimes.
...everything seems to be working as planned and designed. Effective rear brake, no dragging, no overheating, no sticking piston.
I impress myself sometimes.
And the good news is.....
...everything seems to be working as planned and designed. Effective rear brake, no dragging, no overheating, no sticking piston.
I impress myself sometimes.
now you.re learning ...everything can be fixed with a bit of fiddling
.investigation is the tricky bitDeleted account 210609001
Registered user
- Joined
- Mar 19, 2003
- Messages
- 29
- Reaction score
- 7
The overhaul kit has arrived today. Piston, seal, o-ring, spring, and the all important white bush.
So, do I leave well enough alone and save the kit in case it all goes wrong another day? Or replace everything and save the old stuff?
Each time I unscrew the metal pipe from the master cylinder, there's a chance it wont seal properly. And I'll have to cut out the existing white bush.
What should I do?
So, do I leave well enough alone and save the kit in case it all goes wrong another day? Or replace everything and save the old stuff?
Each time I unscrew the metal pipe from the master cylinder, there's a chance it wont seal properly. And I'll have to cut out the existing white bush.
What should I do?
Similar threads
