78 gl1000 front brake caliper issues


Information and questions on GL1000 Goldwings (1975-1979)
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eightangrybears
Posts: 41
Joined: Fri Mar 03, 2017 12:14 am
Location: New Hampshire, USA
Motorcycle: 1978 GL1000 - "Christine"
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78 gl1000 front brake caliper issues

Post by eightangrybears »



So I rebuilt my front forks this past week and I was putting the front wheel back on to the bike. I had cleaned the calipers (didn't rebuild them, although that may be coming if nothing else works) and put new pads in. With the wheel already in place, I was putting the left side caliper on the fork/disc and it wasn't lining up right to slide into place. I put the bike back up in the air, loosened all the axle nuts and shimmied the wheel ever so slightly to allow it to move far enough over towards the right side where the bracket would fit into it's mounting location. I buttoned everything back up and then tested the wheel...it wouldn't move at all.

So I took the axle nuts back off and tried moving the wheel ever so slightly to get it to spin...it did but it was binding on something. I thought it was the speedometer drive but upon closer inspection, it doesn't seem to be that and you can hear grinding of the brake on either a pad or the inside face of the caliper (the C shaped part when it is all disassembled, not the part containing the piston). It is very tough to tell which side is hitting though. I tried to systematically tighten everything to see what is causing the brake to bind and nothing seemed to help. I pulled the brake off (which was tough to pull off of the disc) and was trying to see if maybe the piston wasn't fully compressed. I did the whole "c-clamp on the old brake pad" when I was cleaning/reassembling the brake so I think it is fully in but I can't be 100% sure of that. The pad that sits on the piston side of the caliper seems to be below the level of the C shaped mounting part of the brake (where I think it may be binding) so I don't think it has to do with the piston not being fully depressed and thus pressing on the disc when it's all assembled. And the other side pad is all the way up against the caliper, so technically it should have the maximum allowable room for new pads to have.

My next thought was to disassemble to caliper and bracket and mount just the bracket and see if the disc is actually rubbing against the bracket face or if in fact it is hitting the pad on the non-piston side. I haven't tried it yet though...needed some time to cool down from the frustration!

The only other thing I can think of is the rubber "accordion bushings" that sit between the mounting bracket and the caliper sections that keep the two parts separated a certain distance are too worn. They might be too far gone and thus have been compressed too much and therefore do not separate the two halves far enough to give enough space to allow the disc to fit in without binding.

Does anyone have any ideas or suggestions on what to do? Anyone know what the actual clearance between the two sections of the brake should be? If they are too close together, that could definitely cause this issue and if they are too close, I know it's the accordion rubbers that need replacing but if they compress a lot naturally and the clearance is ok, then I am definitely at a loss and not sure what steps to take next. This particular brake was a bit sticky when it came off the bike but not nearly as bad as now. I would attribute that to the new, thicker pads taking up space the old worn one's didn't but this is my first brake work and not sure what to do about it...

Any help would be greatly appreciated...thanks


1978 GL1000K2 - "Christine" - working on version 3.0 currently
eightangrybears
Posts: 41
Joined: Fri Mar 03, 2017 12:14 am
Location: New Hampshire, USA
Motorcycle: 1978 GL1000 - "Christine"
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Re: 78 gl1000 front brake caliper issues

Post by eightangrybears »

from doing a little more research, it seems like those "accordion rubbers" are just boots to go over the bolt that connects the two halves. So, since they don't do any separating, just keeping clean, they probably aren't the issue here...
1978 GL1000K2 - "Christine" - working on version 3.0 currently
eightangrybears
Posts: 41
Joined: Fri Mar 03, 2017 12:14 am
Location: New Hampshire, USA
Motorcycle: 1978 GL1000 - "Christine"
Contact:

Re: 78 gl1000 front brake caliper issues

Post by eightangrybears »

I tried to mount just the bracket without the caliper just now and it wouldn't actually fit. This means that the wheel is not perfectly placed in the forks. Like I said, I mounted the wheel without the brakes in place so maybe that was my problem? Should I have mounted the brakes and then slid the wheel into place? Maybe just the brackets first? If I mounted just the brackets and the wheel went back in without the discs touching either of the brackets, then I would probably be more likely to not have it bind when I mount the calipers.

Maybe I am just doing it in the wrong order. Or is there a special way to put the axle into its holders on the forks and be certain that it's centered and the brakes won't bind? In my mind, this seemed like such a simple job...

I also noticed that the way I had the dust boots (the accordion rubbers) placed, they were actually keeping the bolt from sitting all the way in and therefore bringing the two halves slightly closer together, which means both the inside pads and the bracket could have been rubbing the disc. But that problem is much easier to solve than the one of how to mount the wheel perfectly centered...
1978 GL1000K2 - "Christine" - working on version 3.0 currently
eightangrybears
Posts: 41
Joined: Fri Mar 03, 2017 12:14 am
Location: New Hampshire, USA
Motorcycle: 1978 GL1000 - "Christine"
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Re: 78 gl1000 front brake caliper issues

Post by eightangrybears »

Here's kind of a strange follow up question: can you turn the wheel around so that the speedo drive is on the other side of the bike? I have seen what seems like Mag wheels have the speedo on the left side whereas wire wheels have it on the right. My bike originally had the mags and I swapped them and the forks out for a wire wheel set up not even noticing it was on the other side until now. The gap between the fork and the disk on the side with the speedo drive is larger currently than the gap on the left side of the bike. If I can use that space to get the disc to keep from contacting the caliper bracket, that might be a way to fix my problem. Almost seems like I need some shims to push the left fork a hair more left to get the disc off of the bracket.

I know I would then have to turn my tire around on the rim, but is turning the rim even an option? I have a feeling the offsets for the discs and calipers are slightly different as well as the fact that the discs have been worn in one direction their whole lives and turning them around may not be the best idea...thoughts?
1978 GL1000K2 - "Christine" - working on version 3.0 currently
eightangrybears
Posts: 41
Joined: Fri Mar 03, 2017 12:14 am
Location: New Hampshire, USA
Motorcycle: 1978 GL1000 - "Christine"
Contact:

Re: 78 gl1000 front brake caliper issues

Post by eightangrybears »

I guess if I had done a little more research on the fork assembly I would have come across "static clearance" and known that if I loosen all the axle nuts and hang the bike (allowing the axle to move side to side in the forks), then I can use a feeler gauge to set the static clearance of the forks. Only thing is, I haven't come across WHERE to use the feeler gauge (is it on the inside of the left fork, the inside of the right fork, at the caliper hanger bracket? And WHAT is the clearance? I am sure it isn't too much but there's probably a number to shoot for...


1978 GL1000K2 - "Christine" - working on version 3.0 currently
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