Can't fit rear brake in drum after fitting news brake shoes

[Seabeowner]

Rear drum is 180mm dia. on 550.  390 is 550F part no. With the shoes centralised on the backplate, what is the diameter?

[alexdecker]

I only took this before I assembled the wheel with the old brake shoes for now. Can you guys make anything of this image?

[Nurse Julie]

That looks to have been relined but you're also trying to fit 750 shoes which won't fit your hub anyway Alex.
Edit... Have you got a photo of the brake plate.

[McCabe-Thiele (Ted)]

Put your ruler across the drum does it look like an I/d of about 18 cms?

If the answer is yes then it's the wrong shoes.

[alexdecker]

I only have this photo of the shoes mounted. The packaging per earlier said specifically they should fit a 550F. So either Vesrah wrongly packaged 750 shoes in a 550 packaging or something else is amiss. But the shoes really are quite a bit longer than the other ones.

[Oddjob]

The shoes look ok mounted Alex, IF they were 750 ones they wouldn't fit. Everything is looking to be correct yet they won't fit. Try measuring the shoes mounted on the plate as per the pic and see what they measure out at their widest point. I do remember many years ago of members saying they had shoes which didn't fit as they just had to much friction material on them compared to the OE shoes. I think the cure was to sand them down until they fitted. I've bought SBS shoes but as yet I haven't test fitted them, must check them to see if they have the same problem.

[McCabe-Thiele (Ted)]

It's not an exact science but measuring the width with the shoes when  in place it's 17.8-17.9 cms measuring from the centre section of the shoes.

[K2-K6]

Take the shoes off the brake plate, then put each one inside the drum to see if there's difference in radius at any particular point around them.

Shoes are often shamferred at their ends to fit then in to the drum, if they touch just at the ends then you can file that ramp onto them easily to get them touching along their full length.

In other words, you may not need to file the whole brake material, just a "ramp" on the end location of the friction material.

[McCabe-Thiele (Ted)]

Is there a big lip on your drum liner by any chance?

[McCabe-Thiele (Ted)]

Take the shoes off the brake plate, then put each one inside the drum to see if there's difference in radius at any particular point around them.

Shoes are often shamferred at their ends to fit then in to the drum, if they touch just at the ends then you can file that ramp onto them easily to get them touching along their full length.

In other words, you may not need to file the whole brake material, just a "ramp" on the end location of the friction material.

Good point K2-K6

[peterengland]

I had the same problem with my 550 rear shoes, filed a bit off the ends and sanded shoes a bit and inside rear hub to get them to fit and no problems since.

[taysidedragon]

I agree with all the comments about the friction material.  If that is not the problem it could be that the new brake cam is too wide and is holding the brake shoes too far apart.