New brakes - Smart Car of America Forums : Smart Car Forum

Fredvon4 · 12-03-2007, 09:37 AM

I noticed on the Brit sites a lot of new owners taking the car back to the dealer because the hand brake was coming up too high

This was unnecessary. These cars have rear drum brakes with a self adjusting feature. From new the factory is supposed to set the brake pad to drum clearance. Sometimes this time consuming step is missed so the "adjuster" was installed in it's smallest dimension and there is a lot of clearance from the drum brake "shoe" "Pad" to the inner drum surface.

There are two ways to set these properly.

One is to remove the wheel tire assy, remove a plug on the backing plate on the back side of the wheel hub axle assy and use a brake adjuster tool or wide bladed flat screw drive to turn the Star wheel on the adjuster anti clockwise extending the adjuster to make the shoes/pads closer to the inner surface of the brake drum. Some mechanics extend out until the brake is tight and drags, and then they reduce back until the drum spins free with zero drag... Other mechanics may use a gage to set the clearance to the recommended factory clearance specification.

The Auto Adjusting feature works by causing the internal links and springs holding the brake shoes to rotate the star wheel adjuster anti clockwise a little at a time. This is done every time you apply the brakes while backing up. The way it is set up you can not over tighten the rear brakes because the action only happens when there is enough clearance for the expanding brake shoes to get wider by a amount larger then the Star wheel tooth spacing. Once set to this width, they will not adjust wider until the brake pads wear down some and the process is repeated on the next reverse braking.

When you pick up your Smart car it is wise to see if your rear brakes were adjusted properly.... Usually you can tell by how far up the hand brake lifts... I think (but do not know the spec) some where from 7 to 11 clicks is about right. Coming all the way up is not. To fix it fast and simple just drive in reverse and apply the brakes 4 or 5 times and see that the hand brake now engages with less clicks... repeat if necessary

**jwight** · 12-03-2007, 09:43 AM

Fred,

Thanks - good info. At least the brakes have the self adjusting feature; our early Mini uses the same adjusting method without the auto adjusting feature in reverse.

jonnysan · 12-03-2007, 10:23 AM

Quote:

Originally Posted by jwight

Fred,

Thanks - good info. At least the brakes have the self adjusting feature; our early Mini uses the same adjusting method without the auto adjusting feature in reverse.

Sure wish they had put disks on the rear...so much better braking and it eliminates all that craziness backing up to adjust, frozen adjusters, all the claptrap cables and springs needed for it, etc.

That might be a nice mod to perform when the brakes need to be rebuilt....convert to disks.
And the MINI doesn't have the auto adjusters so you have to do manual adjusting? Can't believe that....not exactly a 21st century design, is it?

Fredvon4 · 12-03-2007, 10:27 AM

Well I admit I am making a great leap of faith here that MB did not change the design on the 451. On evilutions site I followed the reluctor ring repair photos on a 450 and saw the back side of a rear drum and see the self adjusting linkage exactly is set up as on the back of most of my rear drum cars

Will be a pain if not self adjusting because the area behind the hub is very tight....it will be a serious knuckle busting job to adjust them manually

Fredvon4 · 12-03-2007, 10:29 AM

johnnysan...exactly! I have hours searching for a retro kit for disks on the rear... no soap so far.... arrgh!

I know the drums are good enough but I really really prefer 4 corner disks....

First seriously expensive mod I will do if a kit appears

**jwight** · 12-03-2007, 10:36 AM

Quote:

Originally Posted by jonnysan

And the MINI doesn't have the auto adjusters so you have to do manual adjusting? Can't believe that....not exactly a 21st century design, is it?

John,

It's one of the early British Minis, as opposed to those evil BMW MINIs

Even though they built them into 2000, the rear drum brakes concept never changed from the early 60s cars. The whole car is sort of a time warp.

dblreeder · 02-28-2008, 11:45 AM

Does anyone know WHY the Smart doesn't have discs all the way around?? As Jonnysan noted this would make so much sense!

BandSofC · 02-28-2008, 12:06 PM

I speculate it is because of cost v. performance benefit. Rear drums provide all the stopping power the car can handle while balancing the front to rear bias. Using discs on the rear would be overkill and cost more.
Some of the added cost is probably because (most?) rear disc brakes incorporate a mechanical parking brake too. With a drum brake the mechanical and hydraulic mechanisms can operate the same set of pads.

That said, I'd like to see disc on the rear too. But I understand why I don't need them.

Karl Roth · 02-28-2008, 12:17 PM

My bet goes to $$$ less expensive to integrate parking brake. front disks seem tire limited as delivered
karl
used 87 t-bird turbo coupe stuff on the back of a 5.0 in Germany but then it seemed like it was a good idea to be able to stop more than once from 140...

Fredvon4 · 02-28-2008, 02:11 PM

There is a rear disk kit but much too expensive for my blood...as stated the drums are plenty efficient and I would really only be doing the rear disks for aesthetic ballance...

I very rarely put faux anything on a vehicle so the fake drilled disks are not gonna adorn my rear wheels... that leaves black paint... my plan anyway.... YMMV

OH forgot... my initial note above is partly correct... part of the problem with hand brakes in GB was improper adjustment of the cable slack in the brake lever cable area...