Hi,
This is my first ever bike after passing my full bike license a couple of weeks ago, so please forgive my ignorance.
I have noticed that the front brake on my 2006 GS500F has started binding... I can hear it when riding along sometimes and even more when the engine drops to idle (i.e. quieter), when rolling to a stop for example. If I spin the wheel by hand it rotates about twice at most before stopping. Other than that the brake feels fine and works as expected; it's not spongy at all. It engages with almost no slack on the lever, maybe 5mm at most of slack, which makes sense as the pads are already touching the disk!
I have taken the caliper off, removed the pads (about 4mm left on them), cleaned and lightly greased the slider assembly, cleaned the edges of the pads of brake dust and muck with brake cleaner spray, and the springy thing under the pads, extended the pistons about three quarters of an inch and wiped them off, they retracted slightly, about a mm or two when letting off the brake lever as I read they should, then pushed them back in with a quick clamp and reassembled. Same problem, even after taking for a short ride. I then bled the brake by pumping through about a two reservoirs worth of fresh dot 4. Same problem. After going for a ride for about 5 minutes without using the front brake at all, when I stop and touch the disk it's warm, not hot, but definitely warm.
If it makes a difference it's the Spanish version with the caliper cast with the name AJP on it, as per the top image here: http://gstwins.com/gsboard/index.php?topic=68406.0
I've been taking the car to work as I don't think I should be riding it any distance.
What are the next steps in troubleshooting please? Do I need to purchase a whole new caliper? If so, is there a better caliper than the stock one I should look for?
Thanks.
Tim.
Some rub is normal - IME the pads will always be in contact with the rotor except for immediately following a rebuild. However the wheel should still spin fairly freely and the rotor should not be warm after going for a ride without using the brakes.
I would suggest taking the pistons out entirely and checking the seals, as it might be that yours are swollen up or similar and stopping them from moving smoothly.
If they are then it's a new caliper unfortunately, as for some reason, regardless of where in the world you're based, you will not find the seals anywhere. You'll find plenty of places claiming to have the exact seals for that exact year and country of origin, order some and they won't fit.
An SV650 caliper is a straight swap. The bike is more popular and unlike the GS the calipers did not change every other Tuesday so spares are plentiful. I'm planning on that myself when my seals go.
As the pistons are only in one side.. the caliper has a system to slide the entire caliper in order to press both sides of the rotor evenly... check if it is moving properly (silicone grease is desirable).
I had a honda CB 500.. where the rear brake was jammed... when I changed pads... one side was always scrubbing resulting in a fDuking hot rotor.
Maybe the problem could be located at the master cylinder.. that is no allowing the pressure releasing (less likely).. but one idea to you keep in mind.
Cheers :cheers:
Thanks for your input both. I fully dismantled, popping the pistons out and cleaning them... not much to clean off, they're still nice and smooth. I gently wiped the seals and they felt ok to me. Put it all back together again, bled the brake and still does the same, though very marginally better.
I'll just have to get an SV650 caliper I think. Any year and model will do? Or does that have to match the year of my bike?
I'm guessing I will need two new compression washers for the banjo bolt also?
I'm learning... slowly :-)
Thanks again,
Tim.
Quote from: snuffy on October 24, 2018, 12:31:30 PM
Thanks for your input both. I fully dismantled, popping the pistons out and cleaning them... not much to clean off, they're still nice and smooth. I gently wiped the seals and they felt ok to me. Put it all back together again, bled the brake and still does the same, though very marginally better.
I'll just have to get an SV650 caliper I think. Any year and model will do? Or does that have to match the year of my bike?
I'm guessing I will need two new compression washers for the banjo bolt also?
I'm learning... slowly :-)
Thanks again,
Tim.
When you took the pistons out, did you take the seals out and clean them and the groove they go into? In particular, the dust seal groove. If dirt got in there it could push the seal out against the piston.
Oh as for the second question, you should be good to get pretty much any SV caliper - neither the GS nor the SV have changed the actual mount in
at least 18 years. That said, make sure you get a right-hand one, SVs do have dual front brakes.
How many KMs on the bike? Maybe bearings are shot?does rotation improve when brakes removed?
When you took the pistons out, did you take the seals out and clean them and the groove they go into? In particular, the dust seal groove. If dirt got in there it could push the seal out against the piston.
Oh as for the second question, you should be good to get pretty much any SV caliper - neither the GS nor the SV have changed the actual mount in at least 18 years. That said, make sure you get a right-hand one, SVs do have dual front brakes.
[/quote]
No, I didn't remove the seals, just gently ran my finger around them... they felt smooth and not damaged. Didn't want to damage by taking out as I would be SOL with replacing them if I damaged them taking them out. As it is, and still not working, I might as well try removing, cleaning the groove and refitting on Saturday. I've also read that a thin coating of silicone or red grease on the pistons might help, so I'll do that as well.
Thanks, yes, will make sure I get a right hand one if the above doesn't work.
Quote from: herennow on October 24, 2018, 01:53:22 PM
How many KMs on the bike? Maybe bearings are shot?does rotation improve when brakes removed?
23000 Miles. 37015 KM. No, I can hear the caliper binding, though will double check that when I take the caliper off... yet again.
Thanks.
Quote from: snuffy on October 25, 2018, 09:47:14 AM
Quote from: herennow on October 24, 2018, 01:53:22 PM
How many KMs on the bike? Maybe bearings are shot?does rotation improve when brakes removed?
23000 Miles. 37015 KM. No, I can hear the caliper binding, though will double check that when I take the caliper off... yet again.
Thanks.
Nope, without the caliper on, the front wheel spins and spins and spins.
I take it the noise is constant and not rhythmic? Sounds like you've been focused on the caliper, has the disc been thoroughly eliminated? Just my $0.02
Quote from: Kilted1 on October 25, 2018, 03:15:40 PM
I take it the noise is constant and not rhythmic? Sounds like you've been focused on the caliper, has the disc been thoroughly eliminated? Just my $0.02
Hi, yes, constant, not rhythmic. I'm guessing you're thinking possibly warped disc. Thanks for the thought. was about to do the work this afternoon, and then it started raining just as I got the first bolt out... typical! Hoping for dry weather tomorrow.
So after stripping completely and thoroughly cleaning the seal grooves (they weren't particularly dirty, and no salt build up), I emery papered the slider, and pin, lightly greasing them and lightly greasing the pistons with rubber grease and reassembled. It made very little difference.
I have been riding this week on short slow trips to the office and think it's loosened off slightly.
Might buy some new pads and see if that makes a difference before forking out for a new caliper. I figure new pads might sit differently and I'll use them anyway on a new caliper as I think from looking at pictures that they're the same on the SV650 calipers... though not thoroughly researched that yet.
Update, tried new pads and after bedding them in for 200 miles or so, same symptoms, wheel would spin one revolution before stopping and disk was always hot to touch even when having not used the front brake.
I purchased a Tokico front right caliper off a 2006 750 Katana from ebay and shipped from the USA to the UK (approx £40 total inc shipping). Caliper is in amazing condition, looks new, and can believe it's only done the 8000 miles noted in the ebay description, still has the factory pads with loads left on them. Fitted and after initially having the same symptoms it's now improving... I get three revolutions before the wheel stops, and the disk doesn't get half as hot. The pads are still bedding in after about 100 miles of light commuting, so I hope they'll get better yet. I'll clean the piston seals on the next maintenance I do and that may improve it some more.
Thanks for your advice everyone :-)