brakes grabbing

Alright Fellas, I have a question.

When I lean my bike over to the left and turn the wheel while pusing it, the front brake grabs enough to make it hard as heck to push. I don't notice any problems at all with my front brakes while riding. I only notice this when I have to move the bike around the garage. I have never noticed this happening on any other bike I have owned.

I have new pads, rebuilt wheel cylinder, new aftermarket mastercylinder, new front wheel bearings and SS brake line.

When I jack the bike up, grap the front wheel and push and pull it side to side with my hands, I can't feel any play at all in it.

My theory is that when I lean the bike over it pushes the weight on the side of the wheel and sort of bends the rotor into the pads. But this shouldn't be happening if I have new properly installed front wheel bearings.

 

its more likley that a brake line is getting squeezed from improper installation..... make sure your brake lines are completly straight and free of any tension. if they are twisted or pinched the turning will cause the same effect as pulling the brake lever a little.

if they were right before and you havnt damaged the forks / rotor there is almost no other reason for this.

I had a buddy who years ago put the brake line on backwards on the caliper ... then twisted it into place causing a pigtail like loop in the line ... all is fine while going straight or to the left ... turing right pinched the line causing the front brakes to engage....

 

I had the same problem with mine when I got it. The brakes pads seem to drag on the rotors some. You should remove the calipers and lube the bolts and bushings that the shoes slide on (and keep them centered on the rotors) That's all it took for mine to roll easier. I assume you just have one pad rubbing the rotor and not able to center itself. Worked for me.

 

My issue is similar, but...

My brakes only drag when i'm backing up. Forward, i get zero resistance (I'm getting 53 mpg with my XJ750J).
But when i want to back up, the brakes drag so much that the front wheel will sometimes skid, as opposed to roll.
But ALWAYS and INSTANTLY, when i roll forward, the wheel spins free as a bird.
???
Could i have pads that have worn in such a way as to cause this?
It's just a minor nuance, and i've already put in so much work this winter that i just wanna ride it a while, but a caliper rebuild is in her future...

 

+1 on the shoe slide .... look to see if the pad is the same distance from the rotor at both ends(top and bottom. it could be binding in the slide

good call painter

 

Sounds good, I'll check out the slider.

I know for a fact the line isn't pinched, or installed incorrectly.
The problem is, I don't know if the brakes were right before, I did a complete rebuild on everything from ground up before I ever rode it. And like I said, It only does it when I am pushing the bike around with it leaned over. It's a light bike, so I can manover it fairly easy around the garage, and lean it over fairly far to get it around stuff. It doesn't grab at all until I lean it over.

I am going to check the torque on the front axle, and take off/lube caliper and slides before I ride again, but I have not noticed any problems with handling while riding at all.

 

I have the same problem as HammerheadX. There is no binding when pushing the bike forward, turned right or left or straight; makes no difference. But when I try to roll the bike backwards, the brakes bind, especially with the handlebars turned to the left. Any ideas anyone?

BTW this is a 550 Seca.

 

Ideally disc brake pads run at a zero gap relation to the rotor. Not dragging, but right there ready to grasp.

Bearing drift is usually the mechanism that pushes the pads back after application. In systems that use zero-lash bearings, calipers use what's called a stroking seal on the piston, it deforms as the piston pushes out, wants to return to shape so it pulls the piston back with it when you let go of the brake. IF the piston moves freely, which most don't.

So they drag slightly. Being as how these calipers have a ridiculous single pivot point to allow it to apply both sides, rather than a double slider like most normal calipers, they could be prone to "wedging", which happens in normal systems when a pad is loose or improperly installed...if it digs a leading or trailing edge into the rotor, it becomes "self energized" in the same way a drum brake's primary shoe does, and it drags real hard, powered by the rotation of the rotor...when the direction reverses, the wedging is released.

I suspect it's some kind of combination of these issues....I've noticed mine does not bind, but moans or squeals when I'm pushing it leaned over and turned, so I know it changes how the pads and rotor interact.

The most important point on this brake system is the pin and sleeve that the caliper pivots on...usually you'll find them hopelessly cheezed together. Like I said, it's a minimally effective way of working to begin with. If these two are stuck together, all kind of strange things can happen, since the caliper cannot move normally...

 

Thanks for the insight.....I know the pin and sleeve the caliper sits on is free (not binding) and the pads were able to slide freely while braking and release properly (from what I can tell). So, although braking performance seems OK, the pads themselves may be a little loose against the anti-rattle U-shaped spring and as the holes in the pads are quite a bit bigger than the pin, one of the pads may be deflecting laterally slightly and wedging between the rotor and caliper bracket. Something to check.

I'll rebuild it over the winter and likely get new pads - although not worn down much they are worn deeper at one end than the other, i.e. slightly off parallel with the caliper bracket or with the back of the pads, making me think they never sat in there properly to begin with.

 

Whoa up, the whole lot of you.

Talk about apples and oranges and even grapefruit!

The 650 Maxim and 550 Seca have completely different front brake calipers and a completely different set of issues/causes/effects; and I'm not sure about the 750s.

The 650 Maxim brake caliper has no sliders to lube; it pivots (damndest setup I've ever seen, sorry.)

The 550 Seca has a sliding pin/holding block arrangement, and the advice given does apply to that.

The problem originally posted about is actually probably "normal" considering the design of the 650 Max's caliper (wedge-shaped brake pads and all the 550 is probably suffering from a a need to rebuild the caliper; and/or b a corroded in place "sliding pin."

The 750 I can't help with, unless it has the same calipers as the 550s.

 

Thanks for the clarification Bigfitz......I was not aware of the differences between the 550, 650, and 750 since I only own the first one, but it sounds like what I need to do is rebuild the caliper as a starting point, and clean up the sliding pin (although it does move freely now).

But it does look like the EBC pads I bought may have been experiencing some slight shifting within the caliper housing as they have not worn evenly front to back. In other words, while braking the two pads were not contacting perfectly parallel with the rotor surface, as there is a noticable skew of a degree or two between the worn pad surface and the metal pad backing. One is thicker at the front, thinner at the back, and the other is the opposite - thinner at the front, thicker at the back.

This concerns me - there is plenty of meat left on the pads, but I'm not sure why this happened or if I should re-use them. Should I upload a photo to illustrate ?

 

My 750 Seca does not like to be backed up at a angle but I've no idea why. Rebuilt the master cylinder and calipers with no improvement. I'd love to hear of some ideas...

 

I can tell you for a fact the 650 maxim brake pads are wedge shaped from brand new and none of my bikes bind when being moved around leaned over backwards wheel turned or any thing. I dont have a 550 yet though or an X, YET!!!!

 

No, I understand what you're talking about. Unfortunately, in your case, the sliding pin, holding block and/or caliper body may be worn, allowing an angle to develop between the two that shouldn't be there.

If that is indeed the case, and replacing the sliding pin doesn't correct it, it may be time for a different caliper to rebuild (eBay from a low-mileage bike.)

See if the caliper can "turn" in relation to the holding block with the sliding pin in place. It should only be able to slide straight back and forth. I had one that developed a heck of an angular slop, it had to be replaced.

It's also possible that one (or both) of the EBC pads hung up on the anti-rattle spring and were binding up. I had to "clean up" my EBC pads to get them installed; the powder coater got a tad overzealous on the pad backing plates.

Note that this advice applies ONLY to the holding-block type of calipers such as on the 550s.

 

Mine also squeal while backing it up (straight line or bars cocked). Just recently had the brakes overhauled, but that doesn't mean anything. LOL I will check and lube if applicable and report back. Kind of annoying, thought it might be due to new brake pads not broken in yet.

 

I have checked the slider pin and it is not worn and the caliper body does not rotate at all in relation to the fork mounted bracket. It does slide back and forth (slowly) and only back and forth. The brake pad tops, however, do not seem to fit very tightly in the anti-rattle spring channel and I too recall having to clean them up to get them to properly fit inside in the first place as you did - same reason, too much paint. But can or should the pads be reused ? They have only 1 season on them. Will carefully lubing the anti rattle spring help, perhaps ? Braking performance is not an issue, just the wheel binding while backing up. Especially tough for my wife to back it up with her shorter inseam !

 

I wouldn't re-use the pads unless they aren't that extremely "angled."

Post up a pic or two.

I would NOT attempt to lube the pad/anti-rattle spring juncture unless you do it VERY sparingly like just a wiped film on the surface.

 

This is a most timely thread because I've noticed a similar event with the XJ1100; If I push straight ahead there's no issue. If though I turn the wheel to the left and push, it binds up. To the right there's a tiny bit of restriction but to the left has the most friction.

I'm going to be checking it out this winter & will go over the front brakes in fine detail, they look to be in great shape. The one thing I notice is the front brake lever is hard to compress at all times, works fine but it definitely requires more effort to squeeze than the 650J.

I'll refer back to the thoughts in this thread while I'm looking at the brakes.

 

So, here are the pics of the pad wear skew. I placed both pads together in a vice and took one picture facing the top and one facing the bottom. The difference in pad thickness, front to back, is noticeable. I almost suggests the pads did not sit squarely against the piston and caliper backing when the brake lever was squeezed, or as you suggested Bigfitz, that the caliper housing rotates slightly under braking load, although I checked that and could not see any rotational slack between the caliper housing and mounting bracket.

 

Here's the view from the top......

 

Pads look fine, run 'em.

 

They've definitely got some "taper" at the top that they don't at the bottom. It's nothing to keep you from using those pads though.

In the pics, which is the outer (against the piston) and which the inner (against the caliper body?)

4nik8r We've horribly hijacked the original thread which was in regard to a different style of brake altogether. Start a new thread, or send me a PM. There's a couple things I want you to check.