checking drums for "roundness"

[Dean Moriarty]

I'm in the process of overhauling my braking system.
I've noticed that virtually all the wheels have stiff spots where the brakes appear to bind as you hand turn the wheel. I've tried using the adjusters with little success.
I thought it would be a good idea to get the drums checked for roundness and phoned a local engineering company for a quote for checking and skimming if necessary.

The figure they quoted was £40-50 per drum. I must admit I was expecting to pay a similar figure for all 4 in total.

What is a reasonable figure I should be expecting to pay and does anyone have a good recommendation in the cheshire/lancashire area? Please feel free to PM if we are not allowed to recommend on the open forum.

Many thanks

[David53]

Are you sure they are out of round? Mine also rubbed a little in spots, but I have just backed off one click on the adjuster until no rubbing at all and I still have a firm pedal. I think it's more likely the shoes are not perfectly shaped as opposed the drums. Does your Series II have the older cast hub/drums like mine or the more modern removable drum?

[mike.perry]

Adjust the brakes then push hard on the brake pedal a couple of times, this usually centres the shoes. If they still rub then back off an extra click. It is only a problem if you can feel the pedal pumping when braking.
There is no reason for the drums to go oval as the brake shoes are doing the same as your expensive machinist would do. The usual problem is with scored drums though letting the linings wear down to the rivets, but with bonded linings even this is less of a problem

[MarkyB]

You need to check after they have had a chance to bed in.
Even then you may be able to hear a little rubbing, but unless you can feel something when using the brakes I wouldn't worry about it.

[bmcecosse]

It's normal for the drums to 'touch' slightly as you spin them round - don't worry about it! The shoes can move about on the cylinders anyway - and it's not as if they only press on one part of the drum when you use the brakes - they are pushed on to the whole surface as the drum revolves - at least they will do once initial high spots on the linings have worn away. The price quoted is crazy - and probably a useless operation anyway - what would they have centred on ? The hole in the face of the drum is not an accurate register..........

[Dean Moriarty]

I've had drums that "touch" before but these are either so tight you can hardly turn them at one position of the wheel and free turning at other positions.

[mike.perry]

Have you checked that the pistons are fully retracting?
Have you tried swapping the drums over or the shoes from top to bottom?

[David53]

I'm with Mike - if your adjusters are backed right off and the wheel is sticking then you must have a cylinder stuck open.

[Dean Moriarty]

Fair comment. They did seem a bit slow retracting. I'm renewing all the cylinders as part of the overhall so I'll see if the problem remains.
Cheers

[bmcecosse]

Probably best to use the 'genuine' cylinders then - the non-gen front cylinders have been getting poor Press Reviews recently.....although rears seem to be ok.

[mike.perry]

Try removing the piston from the cylinder and cleaning between the piston and the cap, open the bleed valve and push the piston fully in.

[Dean Moriarty]

Ok they are coming apart today.
As a slight aside, what size brake unions does the Minor use?

[taupe]

Hi

3/8 Unf onto the front cylinders 3/8 BSF on to the rear.

Assuming you have the standard set up-

The rear flexi hose should be standard BSF female to accept the BSF pipe/union from the master cylinder

The other end of the hose is UNF and screws into the rear 3 way T connector the bottom one of the tee is marked with UNF on the casting The other two ways on the tee are BSF to the rear brake cyls.

Although it seems a bit strange to mix these threads it does result in the front and rear hoses being the same ie one end UNF male, other end BSF Female.

Also all the main brake pipes have BSF both ends except for the two short pipes linking the front cylinders.

Taupe

[Dean Moriarty]

Hi Taupe

Thanks for the info.

Just to make sure I've got that straight: Specifically the front flexi hose to copper pipe union is UNF?

Thanks

[bmcecosse]

Yes in fact on my car the front flexi hoses are 3/8" UNF at both ends........

[Dean Moriarty]

Is that because you have Wolseley or Riley front drum set up?

[bmcecosse]

Makes no odds - same fitment for all the sets.

[taupe]

Dean

No the front flexihose to the brake pipes is 3/8 BSF(female on the hose) the other end is 3/8 unf male into the front wheel cylinders which are all threaded 3/8 UNF hence the different unions on the front link brake pipes only. The rear cyls are 3/8 BSF.

taupe

[bmcecosse]

Not mine! I know - because I made and fitted new pipes and new flexis at the front ..... 3/8" UNF both ends.

[taupe]

Yes BMC

But yours is not standard in the braking department

taupe