356 front brakes.

[mycar]

The drum brakes on my 356 do seem a bit hopeless and I'm not sure if it's because I'm so used to servo assisted brakes these days... or that they are in fact hopeless.

To be fair the Brembos on the Volvo are immense and I have rather come to take stopping for granted but even so the 356 requires more forward planning in the slowing department than is sensible.

I thought I'd work towards giving the brakes an overhaul but before I start ordering up expensive bits and pieces I thought I'd have a read and came across an article called 'Backward Braking'

It turns out that drum breaks have an 'energising' and 'de-energising' direction of rotation. In short, the front drum brake shoes have a cylinder at one end and are anchored at the other. When the direction of rotation of the drum is from the cylinder end towards the anchored end of the shoe, the rotation of the drum pulls the shoe tighter against the drum, increasing the braking effect.

However, it is possible to mix the up the parts and if the cylinders are reversed diagonally, everything fits fine but you end up with de-energised brakes that don't take advantage of the geometry.

You end up with rubbish brakes.

So I'm thinking, this could be what's wrong with my car and there's no need to spend a fortune on new parts, I'll just go in .... swap things around... bish bash bosch.

But first things first... I've never taken a drum brake to bits before and I've got books and manuals but all of them just say 'Remove the brake drum'

This is where I need assistance. My {our} car is a T2 '59 and it looks like it has the roller bearings fitted. I say that because it has the clamp type wheel bearing adjusters fitted.



Can anyone tell me how I remove the brake drum and look inside without roller bearings rolling all over the floor ?

[Ashley James]

Having checked that the Pistons aren't sticking, you need to makes sure that the whole of all the shoes are in contact with their drums. We use chalk.

[mycar]

Thanks Ashley, that's a good plan.

Once I've removed the wheel, how should I proceed with the brake drum removal ?

[Lightweight_911]

Mike - the 'rollers' are an integral part of the wheel bearing (they are held in a 'cage') so you don't need to worry about them falling out.

Undo the allen-head screw on the spindle clamp nut sufficiently to allow you to unscrew/remove the clamp nut (through which the speedo cable runs on the lh front wheel in your picture). Then remove the large washer that is behind it. You should them be able to pull the drum off.

Be careful that the outer taper (wheel) bearing doesn't drop out - I usually pull the drum partially off to unseat the bearing then push the drum back on so that the outer bearing can be removed first. Then pull the drum off.

[Lightweight_911]

Mike - the 'rollers' are an integral part of the wheel bearing (they are held in a 'cage') so you don't need to worry about them falling out.

I'd remove the wheel first (some people leave the wheel attached to the drum to give extra leverage).

Undo the allen-head screw on the spindle clamp nut sufficiently to allow you to unscrew/remove the clamp nut (through which the speedo cable runs on the lh front wheel in your picture). Then remove the large washer that is behind it. You should them be able to pull the drum off.

Be careful that the outer taper (wheel) bearing doesn't drop out - I usually pull the drum partially off to unseat the bearing then push the drum back on so that the outer bearing can be removed first. Then pull the drum off.

[mycar]

Thankyou Andy, I'll give it a go.

[jb]

I hope that by posting this someone will tell you the proper way but my understanding is that you undo the nut etc and then pull the drum off either with a puller or - (as suggested on 356registry):-
"Put the wheel/tire on but leave the nuts a bit loose. It becomes a crude slide hammer if you push the wheel in and jerk it out".

Just seen Andy's reply - he knows best I would think.
Also perhaps loosen the shoe adjustment first

[fetuhoe]

The early 356 has single leading shoe front brakes and if you cross them over side to side they become single trailing shoe and lose efficiency.

If the rears have been correctly assembled as single leading shoe it is likely to lock the rears before the fronts.

Trailing shoe front brakes are normally a feature on a Vespa

[mycar]

Do you mean the early cars just had one shoe per side Chris ?

[Ashley James]

Most older cars have one double ended wheel cylinder back and front and often breaking is 50/50, so if anything is wrong on the front that backs lock up first.

Later cars had two cylinders, so two shoes having leading edges forced into the drum. It gives more initial braking and fades more compared to maximum effort, so both approaches have pros and cons.

The main thing is to make sure shoes have 100% contact with drum as best you can.

[fetuhoe]

Do you mean the early cars just had one shoe per side Chris ?

No, its how the shoes behave relative to the pivot positions and the cylinders.


There is a better explanation than I can provide given below.


http://www.engineeringinspiration.co.uk ... .html#LEAD

[mycar]

That is an excellent explanation Chris !

The drums pulled off easily, a lot of fuss about nothing, and revealed Dr Porsche's improved drum brake system with 2 cylinders giving, in effect, 2 leading shoes ?




Both front brakes have their cylinders fitted correctly and everything seemed in order.

The wear limit for the drum is 282mm. Mine are 280.5 with just over 3mm of lining left so all OK.

New shoes have a 7mm lining, mine have a good 5mm left so no need for replacement.

Which left me scratching my head a bit. All within spec but still I have poor brakes. Then the engineer guy from next door came in, sucked his teeth and thought the shoes might be glazed or contaminated or something which was fair comment, so I set about cleaning everything up with lots of brake cleaner etc. The whole lot was pretty filthy but came up really nicely, The cylinders look to be in lovely condition, maybe they're a new addition.

Then just as the wheels went back on, it started to pour down and I had to postpone the test drive till tomorrow.

[Ashley James]

It's worth slacking off the nuts retaining the wheel cylinders slightly, slamming the brakes on a few times and tighten the nuts again while someone holds the pedal down. Then adjust them again.

Also make sure Pistons aren't sticky.

[Winston Teague]

^^^^^^^^^WITH THE BRAKE DRUMS ON^^^^^^^^^^^^

W

[Ashley James]

Thanks Winston, I forgot to mention my dementia.