Strange problem - car won't move

[saturdaygig]

It had been standing for a couple of weeks and I tried to use it monday. It started fine, but when I tried to pull away it wouldn't move, it felt kind of line there was a brick under the wheel - under one wheel even because it sort of slewed as it tried to move. I thought right away, it's not like a stuck handbrake because I think I'd beat that with the engine.
So today I jacked up each corner to see which wheel is the one. Rear onside not moving, so I put it on the axle stand and took the wheel off. Then I noticed it was in gear, took it out and the wheel turned. I'm pretty sure my intial check was with handbrake off and out of gear, but I'd popped it in first because the ground slopes a wee bit, til it was on the stand.
Anyway, wheel back on and the car was fine, took it for a drive all good.

So what can make a car jam like that?

[peter2b]

Might have been hand brake got stuck on 1 wheel by jacking it up could have freed it
peter2b

[saturdaygig]

Do you think the handbrake would be strong enough to hold against the engine?

[pingu]

Do you think the handbrake would be strong enough to hold against the engine?

YES. Because all the drive would go out through the other wheel.

I don't know your circumstances, but I never use the handbrake at home, but rest the wheels against bricks. My handbrake has never stuck .

[saturdaygig]

So how does the handbrake work then? I assume because it has rear disks there must be an independant system for the handbrake.

[Brian H]

There are rear brake shoes inside the drum of the disc.

Parking brake/brake shoes - BMW parts catalog

[motco]

There are rear brake shoes inside the drum of the disc.

Parking brake/brake shoes - BMW parts catalog

Yes, and it's rubbish! We've had three BMWs here and they have all struggled to pass MoT on parking brake efficiency: E46 320 Compact, Z3 (mine), and Z4M Coupé. My Jaguar X-Type and also my Westfield both have discs all round and the handbrakes (using the discs) are vastly better than the peculiar BMW set-up.

[lightning]

The handbrake on my 2002 Z3 is fine, and it went through the MOT with no problems.

[John Wilson]

I've just spent the afternoon servicing the handbrake on my Z3. No problems with it at all. Just take a wheel off, then 2 16mls bolts holding the brake caliper on. Slide the caliper off and tuck it out of the way (be careful of the pipe). Then one screw on the front of where the wheel goes on. Its an allen key. Then the drum slides off towards you together with the disc. I had to use a rubber hammer onto the back of the disc to free it but it wasnt too bad. I can see that bit being a problem if its stuck on. Afterwards I put a tiny amount of grease on where the surfaces come together to stop any problems next time. Then its just turning the notched ring to ajust the brakes, and put everything back. It made a big difference to the brakes - well worth doing.

[peter2b]

Strange my z3 has discs on all 4 wheels has it been model at some time
peter2b

[John Wilson]

There's discs as well as drums on the rears. The drum is in front of the disc that is just used for the handbrake.

[therealdb1]

Lots of different manufacturers use this disc/drum set up for the rear it's not peculiar to BMW. My many large Vauxhalls, Jaguar, Volvo and Porsche all had a similar set up. In fact the only car that I have owned with rear discs that actually used the discs and pads for handbrake was a 1991 Volkswagen Passat and that had its own issues when trying to wind the screwed piston back into the caliper. The drummed disc combination only becomes a PITA when the insides of the drums are corroded and you cannot get them off to work on the handbrake so be warned and keep on top of the maintenance.
At least these systems are purely mechanical and easy to understand just wait until this obsession with fitting electronic handbrakes to modern cars comes back to bite the 3rd and 4th generation owners!!!

[pingu]

... just wait until this obsession with fitting electronic handbrakes to modern cars comes back to bite the 3rd and 4th generation owners!!!

The OEM is not worried about them .

The test for handbrakes is wrong, IMO. It should be a static test, but it's a dynamic test. Corroded drums will fail a dynamic test, but would pass a static test (as long as they can be released).

[peter2b]

cheers John didn't see them hidden behind the disc's
peter2b

[Robert T]

Interestingly, the handbrake is tested to ensure that it could stop the car in an emergency, not just hold it whilst parked/doing a hill start. In order to pass the MOT, cars with single-circuit brakes have to have a handbrake that is twice as effective as a car with dual-circuit brakes because of the increased chance of total brake failure. I found this out because the Sprite failed its MOT on a rear brake - no handbrake or footbrake on one side - the cause was a leaking seal on the axle that caused diff/axle oil to leak into the brake drum and contaminate the pads. It wasn't even noticeable under normal driving at 70% of the braking comes from the front.

Cheers R.

[saturdaygig]

... just wait until this obsession with fitting electronic handbrakes to modern cars comes back to bite the 3rd and 4th generation owners!!!

The OEM is not worried about them .

The test for handbrakes is wrong, IMO. It should be a static test, but it's a dynamic test. Corroded drums will fail a dynamic test, but would pass a static test (as long as they can be released).

Well, I had an S-type fitted with one, right up to 180k miles and still working really well.

[BladeRunner919]

At least these systems are purely mechanical and easy to understand just wait until this obsession with fitting electronic handbrakes to modern cars comes back to bite the 3rd and 4th generation owners!!!

I'm sure the same was said about fuel injection. And the wheel. And fire.

[therealdb1]

True!
I do remember many a Triumph owner carrying bags of frozen peas around with them trying to keep their early fuel injected cars running!
I'm glad Mr Bosch et al got their act together as I for one would never consider a carburettor again.
Wheels are ok provided they come in fours and as for fire, well surely that was discovered for weekend BBQ's!
How do the electronic handbrakes fair in the MOT as an emergency substitute for footbrake failure?
My experience of them is that they appear to be 'on' or 'off' so do they communicate with the ABS to prevent wheel locking if applied when the car is moving? In fact can you apply them with the car moving I haven't tried?

[Hairyscreech]

Speaking as an automotive engineer there is no benefit to the end user or the function of the car from an electronic hand brake, what they are is a benefit to the manufacturers when it comes to not needing to make or route hand brake cables or produce a lever and fit it to the floor pan. Consider the cost of a few solenoids, some wire and a button vs several pressings, 2 cables and the supporting linkages.
I only hear complaints about them, sticking on, going into fail safe, being jerky and hard to control (looking at you vauxhall) and ultimately costing a fortune to fix.

I hear the brake by wire argument all the time from people who should know better the only benefit seem to be more advanced stability control (only needed if your a ) shortly followed by the "it works for aircraft" argument, forgetting aircraft do one hard stop before being checked and are maintained fastidiously, two things than cannot be said about the average car.
The other big factor is aircraft are no so brutally built to a price on the critical systems like a lot of cars are.
Steer by wire falls into the same camp, look at the troubles with the Z4s electric assistance, and that is only a relatively simple system...

Back on topic: The Z3 hand break is the same as the E30, it's a very reliable system and should be able to lock both rear wheels with no problems.
The big mistake is people adjust them up on the cables in the cabin which makes the pads contact the drums incorrectly. If you take one of the wheel bolts out there is a barrel adjuster inside the drum (number 6 in the picture above), this needs to be adjusted up until there is a slight drag with the handbrake off, can be done through the wheel bolt hole with a flat screwdriver, then turned back a little so there is no drag.
Then and only then adjust the lever cables.

[therealdb1]

Don't start me on that topic - A lot of designs these days are about making more money not to improve the product by making it more useful or easier to use. How regularly do we need to update a mobile phone for example? I grew up when a phone that was not in your house was fitted in a red box and you needed to post a few pennies into the slot for the privilage of using it!

Going back to your point yes I agree that often people do not adjust these handbrake systems properly using the cable instead. There is a certain "knack" to locating and rotating those barrel adjusters but patience and perseverance is rewarded in the end.

[Robert T]

I'm glad Mr Bosch et al got their act together as I for one would never consider a carburettor again.

Nothing wrong with carburettors per se. My first car had a carburettor and I never had a problem with it. I think most of the problems stem from having more than one, and then trying to keep them all in balance is a bit of a 'mare - something fuel injectors manage much more easily. I only have a single Dellorto on the Sprite and it is no problem, not least because there is nothing to go out of tune on it and it has very few moving parts.

It took me a while to get used to the Z3 handbrake. If you pull up firmly on the foot brake on any kind of slope, then apply the handbrake, the car will roll very slightly forward or backward until the handbrake pads "bite". The first couple of times you were panicking that you hadn't applied the handbrake and trying to pull it on harder. It's just one of those things you get used to.

Cheers R.

[peter2b]

Swmbo has a c32o merc auto the hand brake is a small button by the steering wheel pull up hand brake ON push down hand brake OFF bit spooky when I first used it, the gear lever is also strange I thought it was the indicator stalk but its up for drive down for reverse
peter2b

[therealdb1]

My last car with a carburettor was a 1978 Opel Manta that I owned in the early 1980's with a twin choke monstrosity. Fine from cold but a hot start - forget it!
In 1986 I bought a fuel injected 1984 Manta GTE and have never looked back. Had it tuned by the legend Bill Blydenstein a couple of years later that was a revelation again. I wonder what happened to that car? If only I had the room and the finances to have kept it.
I guess the Sprite carb is not much more than a Venturi with a fuel jet so provided the fuel is filtered there is not much to go wrong but I bet you can still get a service kit for it!
Drivers were expected to DIY when that was built.

[pingu]

How regularly do we need to update a mobile phone for example? I grew up when a phone that was not in your house was fitted in a red box and you needed to post a few pennies into the slot for the privilage of using it!

Funnily enough, I had to use a phone box the other day when I couldn't get a signal. I spent ages looking for the A and B buttons, then realised it was one of the new fangled ones that you just put some money in .

[Dino D]

Back on topic: The Z3 hand break is the same as the E30, it's a very reliable system and should be able to lock both rear wheels with no problems.
The big mistake is people adjust them up on the cables in the cabin which makes the pads contact the drums incorrectly. If you take one of the wheel bolts out there is a barrel adjuster inside the drum (number 6 in the picture above), this needs to be adjusted up until there is a slight drag with the handbrake off, can be done through the wheel bolt hole with a flat screwdriver, then turned back a little so there is no drag.
Then and only then adjust the lever cables.

Good info. Does correct adjustment remove the lag between pulling the hand brake and the wheels actually locking? On mine there is some slight movement after pulling up the brake until it's secure.

Can you also elaborate on this barrel adjuster adjustment, I'm assuming there is one on both sides. Sounds straight forward but just asking in case!

[Hairyscreech]

Everything you could need to know here: http://www.e30zone.net/e30zonewiki/index.php/Handbrake
E30 used there but the insides are identical on the Z3 (I have Z3 wide arch hubs and discs on my E30 trailing arms).

I don't think there is much you can do about the lag, it is a result of the way the pads sit on the stub at the bottom of the drum.
The pads are adjusted to the drum diameter at the top and pulled open by the expanding wedge (with the cable) at the bottom so this means they "float" a little, the 1" wide metal stub at the bottom by the expanding wedge is what stops them spinning freely, so you get a small rock as they will always have a tiny bit of a gap between the shoulder of the pad and the stub on one side.

Some pads are better than others, I have found the Z3 is a little worse than the E30 in this respect.