H: Hubs, Wheels and Tyres Brake plate runout

[Cyborg]

I'm in the process of sorting out the front brakes on the B twin. The front brake plates that came in the basket were in need of a bit of work and knowing that I would need a couple of more brake plates for a future project, I ordered two new ones from VOC spares. This one is being built to ride, so trying to get things right and get it on the road while I'm still vertical. I went to test fit the new (bare) plates, to establish what I needed in the way of shims to keep them just clear of the drum and found that they had more runout than the old ones. I set up an old axle between centres on the lathe. I took a slight cut off the shoulder to make sure it was running true. Set the plates on the axle and checked them with a dial gauge. One plate has about .016" runout and the other plate (with the speedo drive) has a total of about .070" runout. They have paint on the inside of the plates where they sit up against the bearing and shim, so that might account for a bit of runout if the paint is uneven... but not .070. Am I missing something?

 

[chankly bore]

"Runout" normally assumes something is rotating, so I guess you are looking at a bend or warp. What matters most is that the brake plate pivots are true and square and stay that way, and the plates don't flex when used. Remove the offending paint first and then shim for minimal clearance to the drum edge.Do the final tightening of the E80 nuts with the brakes in place, and the brake held on hard. You will need a thin spanner.

 

[greg brillus]

Block of wood and a good hammer and you can get most of that out no worries.

 

[Cyborg]

With the right side plate, the runout, or warp in is enough that I can't get the plate anywhere close enough to the drum with out it rubbing in one spot. To make it clear, I would have to use a few shims... to the point where the E80 wouldn't go on all the way. Being out that much, it seems to be more than just paint.

I have the required thin spanner, but the new plates are an extremely tight fit on the axles. Way tighter than the originals. I would have to enlarge the holes in order for that procedure to make any difference.

 

[Cyborg]

Block of wood and a good hammer and you can get most of that out no worries.

I went back to the bin and dragged out an old knackered original. I have beaten it to the point where it it now serviceable. I can't say I'm thrilled about doing that with a new one. Especially if I don't get it right.

 

[timetraveller]

Are these steel or ali plates? If the latter then the hole in the centre should be a very loose fit on the axel to allow the plates, shoes etc. to be centralised in the drums. If steel then they should bend, but as you say, that is not a good thing to have to do to new items. Let the spares company know. They cannot improve things if they are not aware of them. You cannot rely on this forum to inform the Spares Company. Some months ago I found out that the eyes at the rear of brand new the lower fork link were twenty odd thou out of line. I later spoke to Ian about it and they had not picked that information up from here.

 

[stu spalding]

I went back to the bin and dragged out an old knackered original. I have beaten it to the point where it it now serviceable. I can't say I'm thrilled about doing that with a new one. Especially if I don't get it right.

It has been said that worn brake cam housings cannot be reclaimed. They can be pressed out, they're not in that tight, and bored and sleeved in a lathe and pressed back in. They should be secured with braze or weld. I rescued a pair of insurance write off plates that were better than the ones supplied by the "expert" to replace them. Cheers, Stu.

 

[Albervin]

I went back to the bin and dragged out an old knackered original. I have beaten it to the point where it it now serviceable. I can't say I'm thrilled about doing that with a new one. Especially if I don't get it right.

If you bought them from a recognised supplier then contact them now. Do not complain to those who can do nothing. Best to do it to those who can do something; either replace them or refund your money. Been there, done that many times and the result is a better part, in the end.

 

[Cyborg]

If you bought them from a recognised supplier then contact them now. Do not complain to those who can do nothing. Best to do it to those who can do something; either replace them or refund your money. Been there, done that many times and the result is a better part, in the end.

I get that... and I will contact them. Although it might sound like I'm complaining, it was more like moaning. Normally, in the past, I wouldn't think twice.. I would just ship them back. Since I started this project, I've had to change my perspective on that sort of thing and modify, tweak, bend, file, etc.... now I'm starting to sound like I'm complaining Anyway... it's always good to get someone elses perspective just to make sure I don't require additional behavioural intervention.

 

[Cyborg]

Are these steel or ali plates? If the latter then the hole in the centre should be a very loose fit on the axel to allow the plates, shoes etc. to be centralised in the drums. If steel then they should bend, but as you say, that is not a good thing to have to do to new items. Let the spares company know. They cannot improve things if they are not aware of them. You cannot rely on this forum to inform the Spares Company. Some months ago I found out that the eyes at the rear of brand new the lower fork link were twenty odd thou out of line. I later spoke to Ian about it and they had not picked that information up from here.

Steel plates.