Rear Brake Problem?

[dirtrack49]

Hi all,

Just got started on a 66 230sl this last week that had been sitting up for over a couple of years. The car actually has only been driven about 15 miles in the last eight years.

When I first went to trailer the car, I was unable to even move it until I got several people to rock the car back and forth assuming the brakes were hung up. This got it to move with a lot of resistance.

After jacking up the vehicle and placing it on jack stands, I found that the left rear wheel is very hard to rotate. I am guessing from what I have read on this forum, it might be the emergency brake hanging up?
When I apply the e-brake it will hold the wheel in place so that I can remove the tire lugs. However, when I release the e-brake, I can hardly rotate the left rear tire due to a heavy resistance, while all of the other wheels on the car seem to move freely.

What would be this boards opinion as to how to go about resolving my current problem?

Also, I am in need of some shop manuals. I see that a Haynes manual starts off at 1968. Are there earlier manuals that are used by the group for the older cars?

Thanks,
Tom L

[seattle_Jerry]

The drums are easy to take off. You need a threaded bolt to go in the three small holes on the drum. That will push off the drum. Make sure the emergency brake is off. On my car the drums were rusty and stuck plus the rear wheel cylinders had leaked, ruining the shoes. Additionally a ton of road debris/brake dust/grease had clogged the emergency brake pulley. I wouldn't be shocked if it was a combination of problems causing your symptoms.

If I remember right, you need to take off the shoes to get to the bolts for the pulley if it is clogged. If you are going through the trouble of removing the springs to take off the shoes, you might as well do a brake job.

[Naj ✝︎]

Take some pictures.
The shoes are handed and the springs need to go back the right way.
Keep track of all the spacer washers.
I had to drill out the pulley pin bolt because it had seized. Its an alumimun bolt.

Naj

[seattle_Jerry]

Also the bolt is a bit of a trick. The one side has a small lip that prevents it from turning. Its easy to miss if the part has gunk on it. The only side that turns is the one with the folded washer. I used a lot of freeing agent to loosen the rust, plus heat, then after getting the nut off put it partially back on to give me something to press against to remove the stuck bolt. The smooth portion of the bolt shaft gets rust on it.

you can tell which way the shoes go by placing them inside the drum. They will only go one way and fit right/have the holes line up with the car.

[dirtrack49]

Thanks Jerry and Naj,

I took the wheel off late last night and figured that the drum would need to come off with some type of brake drum puller/wheel puller. I did not even see the three holes Jerry mentioned to put bolts in to back it off.

When I get off work tonight, I will take a look.

Anyone know off hand what size bolts I need? I might be able to come up with some tonight at work.

If I understand what you all are saying, there is evidently a bolt that seizes within a pulley that the brake cable runs on?

Do I need to be concerned about getting the brake drum to come off with only using the three bolts to back it off?

I really need to look into a shop manual or at least a parts book. Any suggestions?

Thanks again,
Tom L

[mirkwood]

Whoa!! do not use a puller on the Drums! you will break the fins etc on the outside.
 In these cases I undo the two bolts for the wheel cylinders  and remove the split pins for the brake adjustors . turn the bolts for the brake shoe anchors (depending on the model) and in the center of the drum are two 8mm x1 holes, get a pair of 10 mm bolts and screw them into the holes "SLOWLY~!"
The handbrake cable is probably rusted inside the housing . This will prevent the shoes from retracting from the drums where they are stuck . I have resorted in the past to dismantling all of the handbrake parts and pulling the hosung clear of the backing plate , if it moves you are lucky. if not,mix a batch of 50% Acetone and 50% brake fluid. Soak the out side of the cable with this and it may take a day or so, keep pulling the cable until the housing moves on the inner. The drum can then come clear of the axle far enough to see the shoes and givet hem a belt with a hammer and punch vto loosen them from the drum.

A bit of gentle tapping on the center of the drum will free the drum on the hub.

[dirtrack49]

mirkwood, thanks for the heads up. I will leave the pullers in the tool box.

However, I think I am a little more confused. Am I suppose to push off the drum with the three bolts going into the drum from the front, or access what you say are two holes on the brake drum with 10mm bolts? Not being at the vehicle, are you referring to access from the backing plate, or from the drum itself?

I do seem to remember there being three small threaded holes near the center of the drum. Those three holes evidently allow bolts to be threaded into and up against an axel flange, therefore allowing the drum to be pushed off. What I believe you are saying, is that there is a different way of getting the drum to move in order to allow the freeing of the brake shoes? However, I am not sure what you may be reffering to when you say use two 10mm bolts? Could you please elaborate?

Thanks again,
Tom L

[mirkwood]

Sorry i meant three. the holes a 8x1 mm thread but a 10mm bolt as found all over a pagoda are the ones to use .Check the pic. you can see a bolt in one of the holes in a drum (front on a W110 ). you need to be very careful when screwing bolts into them because the threads can strip out very easily .

What i was mentioning was that often,the shoes a virtually glued to the drums by a mix of oil ,brake fluid and rust.
So that means you need to loosen the shoes by undoing the wheel cylinders . Depending on the model there could be two or four bolts holding them to the back plate. You also need to release the pins hold the shoes in place ,that is why you remove the split pins on the outside of the backing plate.
That leave the handbrake cables,you need to loosen it so that the shoes and the drum can come clear of the backing plate. 

[Raymond]

As for manuals, Haynes is better than nothing. It has some inaccuracies. What you want is commonly called the Big Blue Book (BBB).  It's the factory manual, 2-inches thick and covers the related models of the day.  It is frequently available from books4cars.com, or ebay.  There is a CD floating around but I'm not sure of the authenticity or source. 

The 10mm refered to is the wrench size of the hex socket bolt.  The 8mm is the diameter of the shank and 1.0 is the thread pitch. 

[seattle_Jerry]

again make sure the emergency brake is off...its an easy mistake to make. The bolts do a pretty good job of pushing the drums off, you may not need to undo the cylinder. Also don't assume the previous owner put the brakes together right on the last brake job. Mine were all wrong.

[dirtrack49]

Thanks everyone for your help. I can now go forward with the job at hand.

Unfortunately, I may not get to the 230sl this evening since my 06 Mercedes decided to malfunction last night coming home from work. I found that with all of its goofy electronics, it has decided to not let me lock or unlock the doors. It has also shut down its power assisted door closers. Everyone needs power assisted door closers, don't they? I am guessing that it has to do with the pse pump. Now all I need to do is locate the damn thing and figure out what has gone wrong. Wish me luck.

Having too many vehicles of too many types can certainly keep a person busy and confused. But one thing for sure, you really start to appreciate the simplicity of the older cars when dealing with the modern stuff.

Thanks again and I will post here with my results.

Tom L

[Benz Dr.]

As for manuals, Haynes is better than nothing. It has some inaccuracies. What you want is commonly called the Big Blue Book (BBB).  It's the factory manual, 2-inches thick and covers the related models of the day.  It is frequently available from books4cars.com, or ebay.  There is a CD floating around but I'm not sure of the authenticity or source. 

The 10mm refered to is the wrench size of the hex socket bolt.  The 8mm is the diameter of the shank and 1.0 is the thread pitch. 

Don't think so. A 8mm thread has a 13 or 14 mm head on it. A 10mm head is used on 6mm screws.

[Benz Dr.]

Take some pictures.
The shoes are handed and the springs need to go back the right way.
Keep track of all the spacer washers.
I had to drill out the pulley pin bolt because it had seized. Its an alumimun bolt.

Naj

Aluminium bolt? That's interesting..........

[Benz Dr.]

Sorry i meant three. the holes a 8x1 mm thread but a 10mm bolt as found all over a pagoda are the ones to use .Check the pic. you can see a bolt in one of the holes in a drum (front on a W110 ). you need to be very careful when screwing bolts into them because the threads can strip out very easily .

What i was mentioning was that often,the shoes a virtually glued to the drums by a mix of oil ,brake fluid and rust.
So that means you need to loosen the shoes by undoing the wheel cylinders . Depending on the model there could be two or four bolts holding them to the back plate. You also need to release the pins hold the shoes in place ,that is why you remove the split pins on the outside of the backing plate.
That leave the handbrake cables,you need to loosen it so that the shoes and the drum can come clear of the backing plate. 

What split pins are you referring to? The 230SL doesn't have them. A 190SL has them if that's what you're thinking of.
The split pins or cotter pins are on the inside under the brake drum. All there is on the outside of the backing plate is the mechanical adjusters. At least, that's all I've ever seen.

[Naj ✝︎]

Aluminium bolt? That's interesting..........

Try 110 427 0074

Naj

[ctaylor738]

Maybe I missed it, but have you turned the adjusters all the way "in" so that the brake shoes are retracted as far as possible, and that the parking brake cable has some slack in it?   Then squirt some PB Blaster around the center hub, and the drum should come off without a fight.

[Benz Dr.]

Try 110 427 0074

Naj

OK, I'll bite.  What is this part number?

[dirtrack49]

Thanks Chuck, Naj and Dan for your input.

I found out yesterday that the bolts are not M6 6mm which are mentioned in another thread on this forum. That thread "Rear Wheel Bearing Tour" incorrectly states M6 bolts.

Today, I will pick up some M8 8mm bolts that have 13mm heads. Hopefully, this is the correct size? Or, maybe they are 7mm? I am guessing that I need an 8mm standard metric bolt to do the job.

I guess I have been working with SAE for to long. All this metric stuff is making me nuts.

Dan, you are correct as far as the split pins. The only things I see on the backing plate are two bolt heads that hold the wheel cylinder, and two large slotted bolts that must be the brake adjusters.

I would assume that if I were to release the wheel cylinder, back off the two large adjuster bolts and use some PB Blaster or what have you, I should be able to get this fool thing off.

Hopefully, I might get to it tonight if I get lucky.

Thanks again,
Tom L

[dirtrack49]

Oops, I have another problem.

Seems that everyone is saying that the bolts to remove the brake drums are 8mm x 1. Just got home with both 8mm x 1.25 standard/coarse thread and 8mm x 1 fine.

Evidently, the proper bolts are 8mm x 1.25. Standard coarse.

Now I am wondering if there are brake drums out there that take the fine thread bolt? Anyone know for sure?

Tom L

[Benz Dr.]

I'm pretty sure that they're all coarse thread.

[glenn]

Be careful with the three bolts that force the drum off the shoes. IF, the shoes are stuck... A little too much lb-ft(ft-lb)torque will strip the threads.....aluminum drums???

[Benz Dr.]

You are more likely to strip a fine thred than a coarse one. The rear drums are aluminium but they should come off unless the hand brake is on.

[dirtrack49]

Well, lucky for me that I am too darn tired to work on this thing tonight.

The brakes are evidently pulled up on the left side due to the e-brake not releasing on that side only. Very difficult to turn the wheel, but if will move with a lot of resistance.

Looks like the best thing to do would be to back off the adjusters and release the brake cylinder before attempting to release the drum.

I am glad you both told me that the drums are aluminum. I would have never known. Now I will approach this task with more caution.

On another note. I went into town today to find some oil that had zddp or zinc in it. I know that this has been discussed way too many times on this forum and several others that I attend. My guess from reading other threads is that a lot of folks like to use synthetic oils and others use oil with some type of zinc in it. After due consideration, I decided to buy some Valvoline VR1 Racing oil 10w30. However, I can not find this stuff anywhere.
I know this is a tired subject, but anyone know a good source of 10w30 VR1? Or, maybe some type of diesel oil that will do the job?

Thanks again,
Tom L.

[Benz Dr.]

If your wheel will turn that means it's not so tight that it won't come off. One of the problem with alloy brake drums is they tend to corrode against the metal of the axle. Use some anti sieze on the mounting area before you install the drums.

[jacovdw]

...What is this part number?

Dan,

A110 427 00 74 is the part number for the bolt (or "shaft") that secures the cable pulley for the handbrake on the 230SL to the guide for the handbrake cable in the rear drum assembly.

Two is required per vehicle and it is also used on the W110 and W111 series with rear drum brakes.