13 replies to this topic

[Mini-Mouse]

I've just replaced brake cylinders, springs and shoes on both of my rear drum brakes and after refitting the hub and wheels, one side spins freely and the other only just moves with force when pushing by hand. Clearly I need to do some balancing, but how much should they rub?

 

Someone on the pinned topic "Adjusting Disc and Drum Brake Clearance" said that you do not want the drum brakes to spin freely and an elevated wheel can be spun by hand and stop within about 1 revolution, but the source of this information is unknown. 

 

I know I will be using the square adjusters on the rear of the backplates, but I couldn't get them to move on either side using a regular spanner. I didn't want to go all-out on it in case I rounded it off. So my concern is, that after I buy the correct tool, these adjusters still won't budge. Is there anything I can do if this is the case?

 

Also, would a 1989 Thirty have a single or dual hydraulic circuit, or is there an easy way I can find out as I will need to know for bleeding later on.

 

 

Thanks!

[Carlos W]

If you've replaced the shoes then cleaning up the adjusters would've been a great idea.

[Cooperman]

After fitting new brake shoes you MUST centre the shoes onto the drums by tightening the small square adjusters until the drum will not turn at all and the adjusters are tight.

Then back off the adjusters one 'click' at a time until the drum will just rotate by hand but is still rubbing fairly firmly.

Drive the car for a while and then re-adjust the shoes again, making sure they just 'rub' on the drums.

If the adjusters will not turn freely, it will be necessary to strip the shoes off again and free off the adjusters by heating them with a blow-torch and/or penetrating fluid, then lubricating them with WD40 or 3-in-1 light oil.  Once they turn freely and easily re-assemble the shoes and adjust as above.

Edited by Cooperman, 26 May 2017 - 07:46 PM.

[Simont]

WD40 from the back and on the adjuuster inside the drum and buy the correct tool, I've never had one that wouldnt budge eventually

not sure exactly what the manual suggests, but what I do, put the tyre on, and do the adjuster up until you just can't spin the wheel, then back it off slighty until it just moves again

Edited by Simont, 26 May 2017 - 07:45 PM.

[Ben_O]

What you should have done was to clean and free up the adjusters when you have the brakes apart.

 

I would start off by doing that..

[Ben_O]

Oh, and slather the adjuster with copper slip once freed up to keep it that way

[wile e coyote]

Don't get too brutal with the adjusters... heat, lube & persistence will get them moving freely.... going banzai with the force on them is a very easy way of ruining the thread in the backplate - and at 40 quid a pop these days could get painful...

 

Go easy on the copperslip when free - excess grease and brakes never a good plan!... worth cleaning up and sparingly greasing the wedges and their channels whilst apart (again!)

[Mini-Mouse]

After fitting new brake shoes you MUST centre the shoes onto the drums by tightening the small square adjusters until the drum will not turn at all and the adjusters are tight.

Then back off the adjusters one 'click' at a time until the drum will just rotate by hand but is still rubbing fairly firmly.

Drive the car for a while and then re-adjust the shoes again, making sure they just 'rub' on the drums.

If the adjusters will not turn freely, it will be necessary to strip the shoes off again and free off the adjusters by heating them with a blow-torch and/or penetrating fluid, then lubricating them with WD40 or 3-in-1 light oil.  Once they turn freely and easily re-assemble the shoes and adjust as above.

 

Thanks for the comprehensive guide! How much will the adjusters spin when I get them free? Will they rotate fully or just rock side to side in less than a full turn?

[sledgehammer]

+1 on all the above

 

new shoes can rub a bit sometimes , even when in the correct position , (central to the drum)

 

it sometimes helps to take a fraction off the leading edge of the shoe - only take the sharp edge / fluff off ,  to clear the drum (take care if asbestos)

 

as some shoes can have a sharp leading edge , which can grab against the shoe - this is called 'self servo action'

 

I would also like to add , pull the hand brake up a few times , this def helps to centralise the shoes in the drum

 

then check for re-adjustment , a brief drive , then check again

 

it is surprising how correctly adjusted rear brakes can bring the brake pedal up / make brakes feel more responsive

 

the adjuster has a tight spot every 1/4 turn , you want to stop turning in the slack spot in between

 

when a bit of resistance is felt to turning the wheel / drum

[wile e coyote]

Adjuster has 10+ complete turns on it, whip off the shoes & springs and get to it ... winds out the front of the plate i.e towards drum .... wind completely in & out a few times with a bit of copperslip on the thread and you wont have the problem again, adjuster has a four sided conical nose so every 1/4 turn when engaged it'll adjust a little  - you can feel the flats working on the wedges when all's free

[tiger99]

All good advice! To answer your other question, in 1989 dual circuit hydraulics had long been compulsory, so that is what it should have.

[Cooperman]

When the adjusters are really corroded in and won't move, don't 'round off' the square ends. Use heat to free them until they move, then use penetrating oil (note, WD40 is NOT a penetrating oil) to free them. After that use copper slip and light oil to make them move freely.

The re-install the brake shoes/springs and re-fit the drums. 

Finally centre the shoes and adjust as above.

[russo]

Golden rule when replacing cylinders, shoes and springs. Loosen rear adjusters right off, if seized, free up or replace and let handbrake cables right off or better still disconnect from levers by removing clevis pin. You should find drum will slip on now. Adjust rear brakes until drum tight then back off one click until free, then connect handbrake cable and adjust until both sides until drums reasonably firm with handbrake on first click.

[Magneto]

Did the drums have a lip on the edge? could be they needed turning or replacement and are dragging on the edge of the shoe material.