[Hahncholo]

I replaced both sets of brake pads less than 2000 miles ago. The front ones seem to be doing okay, but the rear inner pad (closer to the wheel, farther from the brake piston) is completely out of material and the base of the pad has started scratching the disk.

When I replaced them, the front calipers were easy to pry open all the way by hand, pop in the new pads, and reinstall. The rear ones took more effort and I just couldn't get it to open quite all the way. I tried over and over with my bare hands and then a screwdriver to lever them open but it never got all the way there. When I installed them, it took a bit of grunting to get the caliper back into place because the inside pad was pushing against the disk. I stupidly assumed that once some of the material had worn away, it would stop rubbing and the problem would sort itself out. At first it was a bit hard to walk the bike unpowered due to the friction, but after a while it became easier, so I stopped worrying about it.

Then this week I noticed that my rear brakes were making funny sounds and feeling a bit wooden. I took a look at them and found the outer pad still had a lot of material left but the inner one is completely worn down. Went out yesterday (avoiding using the rear brake as much as possible) and picked up some new pads, but haven't installed them yet.

What should I try this time to ensure that the calipers are able to open all the way this time? Do I need to open the valve and let some brake fluid escape while prying it open? Would cleaning it help? Should I go out and buy a brake caliper spreader? What should I do differently this time around?

Thanks.

 

[AlexB5892]

I replaced both sets of brake pads less than 2000 miles ago. The front ones seem to be doing okay, but the rear inner pad (closer to the wheel, farther from the brake piston) is completely out of material and the base of the pad has started scratching the disk.

When I replaced them, the front calipers were easy to pry open all the way by hand, pop in the new pads, and reinstall. The rear ones took more effort and I just couldn't get it to open quite all the way. I tried over and over with my bare hands and then a screwdriver to lever them open but it never got all the way there. When I installed them, it took a bit of grunting to get the caliper back into place because the inside pad was pushing against the disk. I stupidly assumed that once some of the material had worn away, it would stop rubbing and the problem would sort itself out. At first it was a bit hard to walk the bike unpowered due to the friction, but after a while it became easier, so I stopped worrying about it.

Then this week I noticed that my rear brakes were making funny sounds and feeling a bit wooden. I took a look at them and found the outer pad still had a lot of material left but the inner one is completely worn down. Went out yesterday (avoiding using the rear brake as much as possible) and picked up some new pads, but haven't installed them yet.

What should I try this time to ensure that the calipers are able to open all the way this time? Do I need to open the valve and let some brake fluid escape while prying it open? Would cleaning it help? Should I go out and buy a brake caliper spreader? What should I do differently this time around?

Thanks.

I would take a look and see how the pistons in that caliper look. If they get gunked up they can be a real pain to get back in/retract after braking. If they are dirty you can try spraying them down with some break cleaner to get all that grime off. If it is still having problems after that you might need to do a caliper rebuild.

 

[02bonneam]

Hi, there not seated proply, i use the old pad and a small G clamp to push it back you will get odd wear the piston pad moves and inner pad is ridgid ...cheers

 

[notoriousRAT]

Yep, likely one or both of your pistons is sticking/stuck.

Pull your pads out and pump your brake to see how much/if or which one moves. If one is stuck block the one that moves and push the sticky one out til you can clean it up.

I pulled the front pistons on both my Speedmaster calipers and cleaned them up with a scotchbrite without removing the brake line. They had a ridge of black gunk that I couldn't get off without pulling the piston and I didn't have any crush washers on hand. Since I also didn't have a seal kit I cleaned up the old seals, lubed with brake fluid, and reinserted the lubed pistons and have no leakage at this time. The rear caliper has a frozen piston I'm still working on but cant get the master cyl to firm up enough to push it out. Prob have to bust out the compressor and pull the caliper.

 

[Baltobonneville]

You might be able to remove the pad and get the piston out far enough to expose clean surface (which is usually inside the caliper), then clean it in place, and leave a very thin film of brake fluid on it for lubrication, as mentioned (just wipe it with a wetted cloth). If that doesn't work, do a rebuild, which isn't hard, but you'll have to spend some time bleeding it when you're finished.

https://brakecrafters.com/products/...e-brakecrafter-rear-brake-caliper-rebuild-kit

Brakecrafters also have a kit that includes pistons.

 

[mick 85]

Obviously you need to free up the pistons so they move freely, so that is the first task. But your pad wear issue is fairly common, and seems to be because the floating feature isn't working properly. The pins are probably sticking, and will need freeing andlubricating, or your problem will just reappear. The old link below contains some good pointers and advice

http://www.triumphrat.net/air-cooled-twins-talk/683217-rear-brake-caliper-problem.html

 

[notoriousRAT]

example of a frozen piston, master cyl wouldn't budge it

 

[GaryTheSnail]

Watch this YouTube video. He replaces the brake pads and shows how to clean everything. Hopefully it's just gunk

https://youtu.be/S_hQTi5x0pU

 

[maydaymike]

Your caliper isn't sliding on the pins properly. It needs to be disassembled, cleaned, and greased. The pistons are probably ok.

Sent from my SAMSUNG-SM-G891A using Tapatalk

 

[Cloudy]

As maydaymike said sounds to me like caliper is not sliding on its pins properly. Disassemble, clean and regrease.

 

[Clayland726]

Like mike and cloudy are saying, the culprit should be the pins the caliper slides on. If it were the pistons that were getting caught, the outer pad would also have excessive wear and not the inner (if the pins were working properly). It's important to check the calipers after winter riding because road salt can gunk up the calipers and cause the pistons/ pins to seize.

 

[Tornado99]

I think it's the pins...take them out, put in a drill chuck and clamp drill down (vise or to workbench)...run it low speed and polish the pins with fine emery or 400+ w/d sandpaper. Needs a near mirror finish.. if too corroded, buy new.
You might also have piston issues BC you could not retract them. Use the brake pedal to slowly push out with a block of wood between the pistons and caliper to prevent pushing them out the bores. You should see an ugly band of crud/corrosion...try scrubbing in soapy water with toothbrush. If it doesn't cleanup, try something tougher...brass bristle brush? If too far gone, get a rebuild kit with new pistons.

The rears on our bikes are in the spray zone for road grime and can go bad quickly. Need regular toothbrush service to stay good longterm.

 

[Baltobonneville]

The OP replaced the pads recently. One would think that he cleaned the pins in the process, but maybe not.

I clean the pins, "polish" them with very fine steel wool, then put a very thin film of grease on them. And put a little bit of anti-seize on the threads so I can get them out the next time.

I find that the pads, in both front and back, wear inconsistently between the two sides no matter how clean the rest of the brake mechanism is. I think that it's a function of the design.

 

[Chada]

I serviced my rear brakes last month and I detected a slight wear difference in the two pads. Not much but detectable. My calipers had never been serviced and were amazingly clean after five thousand miles although I did have a large piece of plastic bag packed down in the bottom of the caliper. Never saw it til I took it apart. Nothing was stuck at all and I extended the pistons out a bit and what dirt was on there came off with some brake cleaner. I did lubricate the pins with a small amount of white lithium grease and put my old pads back in as they were not even close to worn out. I think that these pads do wear a bit unevenly even if the brakes are working properly.

 

[Hahncholo]

Followed the Delboy video and replaced the pads. One of the pistons required much more force to compress than the other. I was able to compress it, not even all the way (still had about 1-2mm showing when I put the pads in, other piston was flush with the caliper), by squeezing the brake assembly in between my knees. Cleaned as much as I could and sanded the pins. Was able to slip the brake around the disk with no effort this time, good sign. Although, once I pumped the brakes a few times and rode it down the street, it felt like there still might be some friction, pads could still be dragging on the brakes. I'll have to ride it a bit more to be sure.

 

[rweb]

@Hahncholo Both pistons should be pushed in with your fingers and should require equal force. With the wheel off the ground give it a spin with your hand. If it doesn't spin more than one round remove and clean the pistons and seals, clean the seal groves with a tooth brush,do not scratch.

 

[Pylot7]

So I just replaced my front and rear pads last week end.

When I had the calipers off the bike and the old pads were removed I took a toothbrush and laundry soap in water and scrubbed the pistons good. Got all of that built up gunk off of them. They are chrome looking underneath. After cleaning them you can easily push them back into the caliper. After the soapy water I rinsed them with brake parts cleaner. Then let them dry.

If you push a dirty piston back into the caliper you will force dirt past the seal and there goes your smooth operation.

My pins were filthy too. They would not clean up with just a tooth brush and the soapy water. So I sanded them with some 200 grit paper. Got them nice and shiny again.

So you missed a couple of steps, not a big deal. Go back and repeat. Get the pistons extended and clean them good. Hopefully you have not damaged the seals.

Just another lesson along the path to maintaining your own.:smile2:

 

[Gunboat]

I’ve dirt problem, especially on the rear, is a recurring problem. I’m seriously thinking of doing a relocation using one of the motone brackets. Hoping that moving the caliper up will keep some of the crap out.
Got to say while stripping this & rebuilding I was thinking of some very easy solutions to prevent the problem ever happening (gators for instance)

 

[okitoki]

Your caliper isn't sliding on the pins properly. It needs to be disassembled, cleaned, and greased. The pistons are probably ok.

while I had the rear wheel off during the weekend, I noted the outer pad was pretty worn compare to the inner pad.
Will give this a go and replace both pads this weekend.

 

[Arawn]

Sliding pins are neglected more often than not, you should clean and lube them at least every time new pads are installed.