Right handFront brake intermittently locks on


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agedbikeman
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Location: Bruay la Buissiere, France
Motorcycle: 1995 GL1500 Aspencade with bolt on trike kit, made by Kit Trike Portugal.
2014 Can-Am Spyder RT(sold, glad to see the back of it)

Right handFront brake intermittently locks on

Post by agedbikeman »



Can anyone help please.
Last November 2023, I rebuilt both front caliper, as the brakes were a bit spongy, bike is 28 years old and original calipers and parts replaced pistons for stainless ones, seals and dust seals, re-fitted calipers, left one was much better, right one was marginally better, but rode the bike lots of miles without problems.

January 2024 I decided to rebuild the handlebar master cylinder, bought the kit, although not oem, but from a seller I trust, also bought a HEL braided brake line kit.

Rebuilt the master cylinder and fitted the brake line. Remember, my problem is only with the handlebar lever operated front brake, all other brakes work properly.

Reading a lot about tiny return hole clogged, I paid paticular attention to this, after thorough cleaning M/C, shone a torch in piston tube, could see light in both holes.

The said rebuilt front brake was now excellent, rode 60 miles to Calais, mixed highway and chug chug traffic, got the boat to England, rode about 5 miles further on , bike started to slow down, eventually stopped, FRONT R/H Brake locked solid. removed silver wheel cover, just about to loosen bleed nipple, bike started to roll down hill, brake had released itself before I had a chance to open nipple.
Rode a further 90 miles, Highway, traffic, etc. no problem.

Next day, rode about 5 miles, front brake locked again, this time opened bleed nipple, small spirt, brakes released, rode further 50 miles, over 2 days, then here we go again, released bleed nipple, tiny spurt, then rode about another 100 miles home no problem.

On inspection said brake caliper was binding but not slowing bike down, to removed caliper from bike, had to remove pad pins and drop pads out, pistons not moving easily, would not come out of caliper but could rotate them, my extractor pliers pulled one, but Honda dealer had to remove the other one.

I think heat had damaged new seals, so bought new Honda ones. Without seals, pistons drop in and out of caliper easily, with seals in place can now move pistons by hand.

When I work h/bar lever with empty m/c, droplets of fluid bubble in and out of both holes, so they can't be clogged, to be sure I dismantled m/c again shone a torch and could see light in both holes, also can see spiral bit of m/c piston in big hole so definitely not clogged.

I bought a complete kit of both caliper rebuild parts last November and had no problem of this nature.
All this only seemed to happened after I rebuilt m/c and fitted new braided brake line. Left front brake works perfectly after rebuild aswell.

Any input welcome
Thanks in advance
Alex


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Rambozo
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Re: Right handFront brake intermittently locks on

Post by Rambozo »

Sounds like the piston in the master cylinder is not moving all the way back. The fluid return hole is only open when the piston is all the way back. Make sure the piston is right up to the snap ring. Did you just replace seals, or the piston, too? Aftermarket brake lever? Do you have any gap between the piston and lever when released? (free play)
Did you bench bleed the master when rebuilding it?
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agedbikeman
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Joined: Tue Jun 18, 2019 3:41 pm
Location: Bruay la Buissiere, France
Motorcycle: 1995 GL1500 Aspencade with bolt on trike kit, made by Kit Trike Portugal.
2014 Can-Am Spyder RT(sold, glad to see the back of it)

Re: Right handFront brake intermittently locks on

Post by agedbikeman »

Hello Rambozo, nice to hear from you again, and thanks for your reply.
I replaced the piston complete with seals, after market brake levers have been on the bike for about 4 years and always worked well, I will check the free play but I think you could be on the right track as, I cannot seem to push both the caliper pistons back even with a C clamp, I will investigate further this morning.

the M/C kit was not OEM, unfortunately I think I've binned the original piston but I'll look for it.
If by chance you have an old OEM piston lying around, any chance you could measure it with a vernier? if not , thanks anyway

I'll also check the new one for blemishes on the lever end.

Thanks for your input, it's given me some fuel to work with.
Regards
Alex
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agedbikeman
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Joined: Tue Jun 18, 2019 3:41 pm
Location: Bruay la Buissiere, France
Motorcycle: 1995 GL1500 Aspencade with bolt on trike kit, made by Kit Trike Portugal.
2014 Can-Am Spyder RT(sold, glad to see the back of it)

Re: Right handFront brake intermittently locks on

Post by agedbikeman »

Hi Rambozo,
You hit the nail right on the head, it looks like the new M/C piston was just that fraction longer to make the difference between return hole open or not.
My Aftermarket brake levers, that I modifies 4 yeasr ago from 1800 ones so they worked the cruise control, the oem ones were too big for my little hands and got in the way of my hand guards, but that's another story.
I put the old lever back and the caliper pistons were harder to push than with no lever in at all, so the M/C piston must be over top limit, I filed about 2mm off the after market lever and bingo, I can push both caliper pistons back with my fingers.
My intermittent brake locking must have been so border line, I would never have guessed it. All back together and working properly.

I'm going to do a write up here about caliper and M/C rebuild and include return hole technology, of course mentioning you name in the relevent places.

I searched for about an hour on the internet trying to find a diagram of the flow in these systems but found nothing.

Thanks again Rambozo for your brilliant help and rescuing my sanity

Best regards
Alex
dicky6105
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Motorcycle: 2000 Goldwing 1500SE

Re: Right handFront brake intermittently locks on

Post by dicky6105 »

Hi,

I too fitted aftermarket brake and clutch levers to my GL1500SE.
I found the same issue of the front brake locking on and discovered it was the lever being too large on its pivot point. Filing 2-3mm cures the issue.

At the same time though, i replaced the linked brake system and linked just the front left and right callipers to the front brake lever. I found that no matter how much i bled the brake, it always felt spongy and needed alot of force.

Eventually, after months of messing about, I replaced the new lever with the original. It felt so much better!

My conclusion is that, the aftermarket levers are not manufactured to spec so much so that, the position of the lever to the piston rod must be greater giving less response and force to the brake piston. The length of the lever itself is slightly smaller giving LESS leverage when pulling in the brake. This results in poor braking efficiency in general.
Add to this the chance of your front brake locking up, is reason enough to NEVER fit aftermarket brake levers

Since re-fitting my original lever, I’ve never had any braking issues and they feel as they should.

Having joined the front callipers together, makes the braking a little more responsive for such a large and heavy bike in my opinion.
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agedbikeman
Posts: 271
Joined: Tue Jun 18, 2019 3:41 pm
Location: Bruay la Buissiere, France
Motorcycle: 1995 GL1500 Aspencade with bolt on trike kit, made by Kit Trike Portugal.
2014 Can-Am Spyder RT(sold, glad to see the back of it)

Re: Right handFront brake intermittently locks on

Post by agedbikeman »

Hi Dicky
Thanks for your reply, at least I now I wasn't imagining things.
I fitted A/M brake levers for 3 reasons, 1, they were looking very worn and faded, 2, my hands are quite small so the new ones were adjustable, 3, the oem ones are so long, I couldn't fit hand guards, neccesary when you have heated grips.
They worked fine for 3 or 4 years, then I decided to rebuild the master cylinder and fit a braided line, I didn't use an oem rebuild kit, pity I was a bit hasty binning the old piston, but I'm sure it was about 1/2 a mm longer than the oem one. the lever was 1/2 mm bigger than the oem ones but worked ok, but the new piston was the last straw and caused the problem. They're working fine now so I'll leave well alone.
Nice to talk to you, stay safe
Alex
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Hondadoc
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Re: Right handFront brake intermittently locks on

Post by Hondadoc »

I made the mistake of buying aftermarket levers once, I knew it was a mistake when I bought them but did it anyways. Thankfully I got stuck in bumper to bumper traffic so I could smell my brakes smoking on soon to be red disks, never again!
In my version of heaven when you get there all your pets will be waiting!
User avatar
agedbikeman
Posts: 271
Joined: Tue Jun 18, 2019 3:41 pm
Location: Bruay la Buissiere, France
Motorcycle: 1995 GL1500 Aspencade with bolt on trike kit, made by Kit Trike Portugal.
2014 Can-Am Spyder RT(sold, glad to see the back of it)

Re: Right handFront brake intermittently locks on

Post by agedbikeman »

My aftermarket levers worked well for about 4 years with only adding something to work the cruise control as I couldn't find direct replacement 1500 levers, had to settle for 1800 ones and mod them.
They worked very well, it was only when I rebuilt the M/C the problem began, my theory is, the AM lever was about 1mm bigger at the heel, but that wasnt a problem, I think the the end of the new piston was also 1 mm bigger and the system just couldn't handle 2mm, after grinding 2 mm off the heel of the lever, all worked perfectly again.


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