Topic: 78 750F rear brake issue

[radarlove]

Second day of riding a newly purchased cb. Loosing speed and i realized the rear brake was on fire.
I put fire out, and pulled off caliper, and saw that bracket too was rubbing.

How do I fix this?

[martin99]

If the disc isn't warped and it's running true I'd replace the bracket, but a bigger concern for me would be how the PO could sell it to you in that state anyway? I suggest you give it a good looking over before you ride it again.

Has that wheel rim been welded?

[radarlove]

Whats the easiest way to tell if disc is true?
Where do i find the bracket?

[Cougars750F0]

 The left and right wheel spacers may need to be switched. If you think the disk is warped you can take it off and check it by laying it on a true flat surface perhaps some thick glass. If the bracket is bent you can post that you're needing on in the Bikes & Parts Wanted - That YOU are looking for in this forum http://forums.sohc4.net/index.php?board=45.0 Get yourself a manual if you haven't allready. Good Luck with your repair.

[CB750R]

Might want to post up a few more photos for reference, have you made sure that there's no missing or loose bolts in the brake arm or caliper causing the brake to shift under load?

your going to have to get the disc free from whats rubbing then do a visual check on the rotor to see if its warped, spin the wheel while holding a sharpie marker VERY steady, and close to the face of the rotor, get it closer and closer and see if the marker leaves any marks indicating a warp... if its bad bad, you will just see it visually. but the marker can help if its slightly warped...

I'd hold off rushing off to buy a new bracket before determining for sure it is to blame.

Oh and welcome down the Rabbit hole, hope you have a good tool box full of Metric wrenches!

[Wobbly]

[martin99]

I do not think it is a spacer problem. From the photo it looks as if the disc is canted over in the bracket. I would check -

Warped disc
Bent caliper bracket
Bent swing arm
Wheel bearing failure (unlikely)

This is why I asked about the rim. If the rear end has been broadsided it might have bent the swingarm, bracket or both and led to some dubious repairs.

[Wobbly]

By now the rotor might be warped even if it wasn't the culprit. Warped rear discs are rather rare on these Hondas. Looks to me, as if something essential is fundamentally wrong. Check the entire rear wheel/brake assembly. I be very suspicious by now. And ever since I joined this forum, nothing surprises me anymore either, and I am always in awe. Those rims cannot be (as in should never, never be) welded, but here--everything is possible. "Dubious repairs" is what you might want to be looking for indeed.

[radarlove]

Easiest way to check if swingarm is bent?

[Black 750K8]

You need to just sit down and read. The Honda factory service manual can be down loaded on this site for free. This is your new bible. When I get a new to me bike the very first thing I do is go through both brakes. Make the bike safe before any thing else. Take off both wheels look over the brakes bearings tires chain & sprockets cush drive. Don't EVER go by what the PO said has been done. If you do it your self you will have more peace of mind that it was done right. Like what has been said you first need to find out what is wrong before you start looking for parts. You never did say if that wheel has been welded or not. I see you are looking for a set of Lester mags. I think once you start taking it apart you will see what is wrong and there will be a ton of help here.