HubDrum

[silloyd]

I have a set of 9" front brakes that I want to fit and I just want to check something with the collective please...

Clearly I need to remove the hub to swap the backplates but, having never done this before, can someone confirm the following:

Do I need pullers to get the hub off or is it better done some other way? If pullers, will the three legged variety suffice?

In the process of removing the hub, is it likely that the bearings will be destroyed or are they likely to be reusable?

Thanks in anticipation.

[IslipMinor]

The bearings should slide off the stub axle without the need for a puller, but this is not always the case, and it is the rear (inner) bearing that can cause the problem.

3 scenarios after using the puller:

1. The whole hub comes off complete with bearings - great!

2. The inner bearing stays on the stub axle, but is complete and when you attempt to pull it off the stub axle it 'falls apart'! The bearings are 'angular' contact, so will not take much axial force to 'pop apart'. If this happens, you will need to get the inner race off the stub axle, which can be a bit of a pain. Once off, clean up the stub axle where the inner bearing fits with some 180 or finer wet 'n' dry, so that the inner bearing will just slide on a clean and greased stub axle. Then make sure that all the balls are in the cage, clean everything up, grease liberally and knock the bearing back together. Sounds a bit of a bodge, but it is not and the bearing should spin freely and be perefctly re-usable, assuming it was in good condition in the first place.

3. The hub comes off, but leaves the inner bearing inner race on the stub axle - see 2. above. This is probably the most common result.

If there is no play in the exitsing wheel bearings, I would re-use them as many of the aftermarket replacements have been known to cause problems, but in scenarios 2 and 3, the oil seal can get distorted, expecially 3, so I would definitely replace both sides, whether you replace the bearings or not.

Have fun!!

[bmcecosse]

I have only ever undone the nut (note LH thread on the LH side....) and tugged hard... If stiff - two tyre levers one on each brake cylinder and it will pop off. The bearings should not be disturbed. The whole job should take less than an hour per side! Put cling film over the master cylinder opening -with the top screwed back on by hand - to stop excessive oil running out when you turn the backplate off the flexi, and immediately turn the new backplate on to the flexi - before fitting the backplate to the kingpin.

[silloyd]

Thanks gents that's nice and clear, much appreciated.

I'll be replacing the (faulty) master cylinder and the (scuffed) flexis at the same time and I'll take the opportunity to flush and replace the fluid, as I don't know how long it's been there, so I'm not bothered about losing the fluid but thanks for the tip.

Three further questions:

1. When repacking the bearing will LM2 grease be good enough or do I need something more substantive?
2. Is 55-65 lb./ft the correct setting for the castellated hub nut?
3. Should I prime the slave cylinders before installing?

[bmcecosse]

Yes/yes/no......

[silloyd]

/ /

Ta

[silloyd]

Thought of another question...what kind of gasket/seal goes between the flexible hose and the slave cylinder please?

[linearaudio]

No seal or gasket, it has an end like that on the end of a metal brake pipe, which bottoms out to make the seal as you tighten the end.

Please, please, don't forget that the hub nut on the left stub axle is a left hand thread!! I've come perilously close to wringing it off in the past by turning it the wrong way when I have been distracted!

[silloyd]

Thanks linearaudio.

That'll be righty loosey, lefty tighty then

[bmcecosse]

[mike.perry]

Which wheel cylinders are you using? If you are using the Morris cylinders then the slots in the back plates will need modifying slightly

[silloyd]

These are Riley brakes, so using the original Girling cylinders with new seals

...and yes I know the consensus about hard pedal,etc.

[bmcecosse]

The hard pedal is just hearsay - report back to us what you find! I'm sure they will be great brakes.

[silloyd]

OK, I've checked the ends of the flexible pipes and they are not in any way tapered to form a seal and even if they were, they're far too short to reach the bottom of the hole in the cylinder.

Further checking here (item 23) suggests that there should be a gasket (copper washer?) to form the seal.

Views?

[Neil MG]

Absolutely correct, there is a copper sealing washer necessary on the hub end of the brake hose.

[bmcecosse]

If your hoses don't have the taper end - then yes - copper washer. Was there no washer present when you dismantled your brakes?

[silloyd]

I haven't taken the old brakes off yet (job for next week), they're caked in 'carp' (misspelling!) so I can't actually see whether there's a washer there or not.

[bmcecosse]

There will be.

[IslipMinor]

Hopefully a bit of myth busting!

The table below is based on a set of design formulae supplied by a past Design Manager at AP Lockheed, who know a thing or two about brakes!!

[frame][/frame]

The top rows show 3 combinations of rear brakes - Minor Series II and early 1000 with 7" front brakes (7/8" rear cylinders), later 1000 with 8" fronts (3/4" rear cylinders) and the Wolesley rears, which are 8" diameter.

The left hand column lists the various combinations of front drum size, master cylinder bore and some common (older) disc brake conversions. Again there is a change of master cylinder bore at the same time as the change to 8" front brakes - it was reduced from 7/8" bore to 13/16".

The combinations in the red borders are the standard Minor 7" and 8" setups (the green one is ours, but we also have a high boost ratio servo as well).

For a Minor with 2 people, full fuel tank and no luggage, the main table shows, for all the listed combinations of front and rear brakes, the resulting front/rear brake balance and the pedal pressure required for a 1g stop, which is easily achievable by good radial ply tyres, even if the brakes might not quite get there.

One thing that really comes out is that the later, smaller bore master cylinder reduces the brake pedal pressure by 9%, with no other downside, so that is worth fitting if it needs changing - not sure if the earlier one is still available? Also the earlier, larger rear cylinders gave much too much bias to the rear brakes.

What seems to work and what doesn't?

Brake pedal pressures, no matter what combination is used, are far higher than a 'modern', so for ease of driving a servo is a good idea - doesn't make the brakes work any better, just avoids the 'ooh er' moment when jumping into the Minor after a modern! Even the best Wolesley setup has about twice the pedal pressure compared to a typically higly servoed 'modern'.

The later 8" fronts are definitely much better than the early 7", so long as the smaller bore m/c is fitted and the later smaller rear cylinders to improve the front/rear balance.

The Wolesley 8" fronts work very well so long as the smaller bore m/c is used and also the brake cylinders are swapped for the larger diameter Minor ones - the original Wolesley cylinders are rather small diameter and would need a higher pedal pressure than the 8" Minor.

I'm not sure about fitting the Riley front brakes at all - sorry! The cylinders are even smaller than the original Wolesley, and cannot be changed, and even with the smaller bore m/c the pedal pressures are higher than the 8" Minor setup. With a servo to give a better feel, there is lots of reserve with the big wide shoes, but without??

I believe that discs are needed for any sort of really enthusiastic driving, and as the pedal pressure are still quite high, to match the expected 'feel' of the brakes and be nice to use, a servo is a very good idea.

[bmcecosse]

Hmm -without some clues I'm not entirely sure what this table shows....... The down side of the smaller diameter mastercylinder is longer pedal travel. I can say that with one set of new shoes on my W brakes the pedal pressure is far too light - and with an older set it's 'just right' , for me anyway. So I suggest friction material coeff has a LOT to do with it. The fact that discs have no 'self servo' action does mean that they often need a vacuum servo to keep the pedal pressure acceptable. I never ran a servo on my Minis - even the Rally S with DS11 /VG95 pads/shoes - and it was fine once they had warmed up a bit! My most recent Mini I converted from drums to discs with Fiesta calipers - best Mini brakes I ever had and again no servo required. But the Mini is of course a small light car. My TR 7 with servo has very heavy brakes - I suspect the discs/calipers are same as a Marina or possibly Spridget.. The brake pads used are same as an Austin 1100 (and Mini). They do work well enough - I just have to push hard. And yes - the servo works - I've tried them with the engine off and it's like pushing against a wall.........