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Drum brakes question
https://www.ausmini.com/forums/viewtopic.php?f=2&t=82300		 Page 1 of 1
Author:  Jackolow [ Fri Aug 02, 2013 6:51 pm ]
Post subject:  Drum brakes question
Last week I discovered that my handbrakes are... well.. useless. Needs adjustment, or so I am hoping anyway. I pulled off my drum brake cover to have a look. Had a seized adjustment bolt but I've done enough reading to know that I whack it with penetrene and thar she goes.

I put the wheel back and tried to adjust the brake adjustment but I think I hit full adjustment before I was able to lock it up - which is something I was able to achieve on the other side.

I don't know much about drum brakes but I think there is enough pad on it. Brake apply does push the brakes in and out quite convincingly.

Image
IMG_1152_resize by Jackolow, on Flickr

What am I doing wrong? I'm pretty sure that I'm supposed to get brakes to rub with the adjustment.
Author:  drmini in aust [ Fri Aug 02, 2013 7:10 pm ]
Post subject: 
Firstly, your front shoe is on upside down.
Then check the other side too it should be a mirror image of this side.

Secondly, if there looks to be a lot of lining material but you run out of adjustment, the drums may have been machined oversize and the thicker linings have worn. Standard oversizes are + 1/32" and + 1/16".

The standard drum is 7" diameter. These days it is cheaper to buy 2 new drums and new shoes from (for example) Karcraft, than get your drums machined and oversize bonded linings/shoes supplied by a brake shop.
I know this because I have just done the exercise. It stops better too than it did with the local bonded linings.
Author:  TheMiniMan [ Fri Aug 02, 2013 8:01 pm ]
Post subject: 
nah the rear shoe is on upside down
Author:  TheMiniMan [ Fri Aug 02, 2013 8:04 pm ]
Post subject: 
Image

this is the other side but still , same-o same-o
Author:  TheMiniMan [ Fri Aug 02, 2013 8:05 pm ]
Post subject: 
oh & yes you probably have oversized drum that side (maybe)
Author:  TheMiniMan [ Fri Aug 02, 2013 8:28 pm ]
Post subject: 
oops ,,, & your upper spring is actually a lower one,,, so you probably have worn a small groove in your hub from the upper spring being fitted to the lower position :-) so now the spring may well be quite thin in the middle :-)

edit--> unless of course there has been 2x lower springs fitted :-)
Author:  drmini in aust [ Fri Aug 02, 2013 10:42 pm ]
Post subject: 
TheMiniMan wrote:
nah the rear shoe is on upside down

Oops so it is, my bad... :oops:
Author:  Jackolow [ Sat Aug 03, 2013 12:33 am ]
Post subject: 
meanwhile in my mind "maybe it's good that this car was unregistered upon arrival. What was the dropkick before me doing to this car??"

Cheers guys - really glad I put the picture up.
Author:  drmini in aust [ Sat Aug 03, 2013 11:03 am ]
Post subject: 
Jackolow wrote:
What was the dropkick before me doing to this car??"



He's not the only one, my mate just found his van bought last year had the same rear brake setup.. :evil:
People either don't rtfm, don't take note of how stuff comes apart, or just don't give a sh!t.
Don't get me started on people who force metric bolts into holes that were once threaded UNF... :x
Author:  Mick [ Sat Aug 03, 2013 11:08 am ]
Post subject: 
From memory, it's not the easiest thing to distinguish in the manual.

The drawing above helps obviously, but isn't from the manual.
Author:  Jackolow [ Sat Aug 03, 2013 4:03 pm ]
Post subject: 
flipped the brake shoe, tightened the crap out of the handbrake. It doesn't really ever 'lock up' if i am to turn the wheel manually, but it does get pretty tight. I think it'll live for a bit longer, but I'll probably look to get new drums and pads anyway. It's not too expensive.

Cheers guys
Author:  dalmeny [ Sat Aug 03, 2013 4:57 pm ]
Post subject: 
I would also check that the adjuster pin thread in the backing plate hasn't stripped. If stripped can slip back to no adjustment every time you apply the brakes. :wink:
Author:  timmy201 [ Sat Aug 03, 2013 9:40 pm ]
Post subject: 
Might be a silly question, but have you been adjusting the handbrake adjuster as well, or just the drum adjuster?
Author:  mini_mad_matt [ Sat Aug 03, 2013 10:31 pm ]
Post subject: 
On the topic of rear shoe arrangement, i'm going to put my hand up and say i assemble the rear brakes as in the first picture. I'm not going to argue that i'm right and i'd be inclined to believe TheMiniMan purely on his word but i will say my reasoning.

My reasoning is to do with the wedge effect. Now you have the leading edge of the shoe in place so that the forward rotation of the wheel pushes into the leading edge right? Otherwise drum brakes aren't very effective. So what about when you go in reverse? If you have one shoe leading and the rear shoe trailing so to speak, then you have 50/50 forwards and reverse and with the front drum brakes you have twin leading. That's the way i've always looked at it so is my reasoning sound or flawed, without using the argument of that's not how the manual says.

My second reason is i thought i did infact look in a manual and see it pictured with both leading edges at the top. Don't ask me which manual though because at work there is a variety to choose from. Although next time i'm there i might go check them all.



Regardless of all that however, it won't be the reason you can't adjust the drum. My only advice there is to back the handbrake off all the way and then use the adjuster on the backing plate. If using the adjuster can't lock up the wheel then you have a sizing issue or a problem with the adjuster or the little pieces the adjuster pushes on.
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