Handbrake weirdness - wide five squareback, rear drums

[petew]

A bunch of you no doubt saw my post a little while back asking about hydraulic handbrakes. It's related to the problem I'm about to describe. I'm having an issue with the right back (driver side for me) rear drum. Basically, the handbrake isn't locking it up on this side while the other side was excellent.

The drums is adjusted correctly and the handbrake cable is well tensioned. I've yet to pull the drum. However from what I can see on my finger having put it through the adjustment hole in the front, the dust is dry and almost black. There does not appear to be any oil in it whatsoever. Nor is there any oil or fluid leaking from the bottom of the drum. I did wonder if it was a bleeding problem, but the pedal is pretty good and the handbrake isn't affected by the fluid lines.

The only thing I've noticed is that when turning the drum to adjust it, the drum turns freely but then catches at one point. It might be slightly out of round in one point. I know this is not ideal, but it shouldn't stop the handbrake working altogether.

Thoughts?

[petew]

Ok, so I pulled the drum off today and had a look inside. I've tried to give you as good a pic as I could so you can see what you think. Here are the pics...

IMG20170805144928.jpg

IMG20170805144729.jpg

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What I don't understand is, there doesn't seem to be any real sign of oil in the mechanism, on the drum surface or on the shoe. There was dust, but not really anything else. Or I am looking at this wrong?

[66brm]

How polished is the drum surface? It looks quite smooth, try scuffing it up a bit with some emery to take the "glaze" off it, should help it to bite better. Have you replaced the cables recently?, you can add a touch more pressure to that side by shimming with washers under the nuts at the handle if one cable has stretched more than the other

[petew]

How polished is the drum surface? It looks quite smooth, try scuffing it up a bit with some emery to take the "glaze" off it, should help it to bite better. Have you replaced the cables recently?, you can add a touch more pressure to that side by shimming with washers under the nuts at the handle if one cable has stretched more than the other

The cables are really not very often used. I have the car sitting in the garage with blocks. Even still they're not very old and yes, I've already shimmed them. I might try scuffing the drums. I would buy a new set, but I was warned off the italian replacement ones that are for sale now. Apparently they have a tendency to fracture and the whole wheel can come off the car.

[66brm]

Yeah I remember reading something about a couple of failures, mostly on race cars running t1 drums, the center breaks away from the wheel mount flange under high loads

[petew]

I've priced new drums... $400 before shipping it seems. Looks like I'll do the brake test for certification and see if that goes ok. If not, I might have to look into a rear disc setup.

[petew]

Right, so in the interests of making things work right for certification, it's getting new (brazilian) drums and shoes. Not cheap, but I think worth the effort. Hopefully that fixes the handbrake issue.

[5.0 Chero]

So I am not a vw expert but but I do not see the drums or shoes being an issue, Have you tried loosing up the left side cable and seeing if you can get the right side to lock up from what I have seen on my 64 bug the parking brake dose of use any sort of equalizer system on the cables so if one locks before the other it will prevent the cable on the opposite side from pulling far enough to lock the wheel

[petew]

So I am not a vw expert but but I do not see the drums or shoes being an issue, Have you tried loosing up the left side cable and seeing if you can get the right side to lock up from what I have seen on my 64 bug the parking brake dose of use any sort of equalizer system on the cables so if one locks before the other it will prevent the cable on the opposite side from pulling far enough to lock the wheel

Yeah, the later cars have a "balance bar" set up. Mine doesn't. It's all in the adjustment. Even with the right side adjusted up super tight, it still didn't want to lock properly. I honestly think the drums are way past factory specs, probably the right more than the left. Hence why I bit the bullet and bought the new drums. I seriously considered buying a disc setup, but that was going to start at near $800 (I'm not buying Empi rubbish). That's 2 sets of drums and shoes are cheap, $30 a set.

[petew]

Went to pick up some new shoes to go with my new drums... and then I saw this and realized how much of an amatuer I am. How do you even get a wheel over this? Apparently it belongs on a bimmer of some sort.

IMG20170831161053.jpg

[Marc]

What year are the shoes? Are the frames angled at the adjuster end like the new ones shown in your most recently posted picture or are they "square-ended"? I'm unable to see clearly either the adjuster screw slots or the ends of the shoe frames in the first picture, but the far adjuster is either an early straight-slot type or a `65 or later angled-slot that's installed upside-down.

If the angle of the end of the shoe does not match that of the adjuster, the shoe will catch on one end of the slot rather than slide freely up and down, resulting in a "false" adjustment as well as uneven wear and parking brake action. Installing angled-slot adjusters upside down (or mismatching the shoe frame and adjuster styles) is undoubtedly the #1 rookie mistake on VW brake jobs.

It's important that the lining be ground to a radius slightly smaller than that of the drum - when you hold the shoe up against the drum and squeeze it tight at one end, there should be a slight gap at the other end...exactly how much is less important than that both sides are roughly the same, but let's call it 1mm. Few shops have the necessary equipment to "arc" linings anymore because of environmental regulations, but any place that does the actual application of lining material to shoe frames must have it on-site.

The size "limit" cast into the drums is based upon being able to achieve a satisfactory radius-match with standard-thickness linings (without having to grind them half off in the middle to do so). VW used to provide "oversize" linings that were .5mm thicker than standard, and with those it was authorized to turn the drums an additional millimeter beyond the "maximum" spec....of course, most machinists were reluctant to do so because of the potential legal liability (since it was beyond their control what thickness linings would be used) - one might have to sign a waiver to get the job done. Personally I'd rather run original German drums that were turned "oversize" (provided I had thicker linings built and arc'ed to them) than brand-new Italian or Brazilian junk. See first remark here (the 1970 "Without Guesswork" manual provided by VW): https://www.thesamba.com/vw/archives/ma ... 10_111.jpg

[petew]

Hi Marc,
Thanks for your tips. I'll keep them in mind when I'm putting it all together. I've got the early setup with angled ends. This is second car I've had this setup on. I'm pretty confident with the mechanism. I got it down to a fine art on my old buggy.

I've actually got another pair of early drums, but I'm pretty confident they'll be as badly oversize as what I already have. I think the driver side drum on the car is slightly out of round. So we'll try the new ones and go from there. The only thing left to replace is the handbrake cables after this. Who knows, the cable tube might be loose inside the tunnel... but I hope not.

[Marc]

...I've got the early setup with angled ends...

The angled-end shoe frames and wider/angled adjuster slots debuted for 1965; those would be considered the "late" setup.

[petew]

Cheers, thanks for the clarification. I think the backing plates are late backing plates.

[petew]

Right, so I've sorted out the problem. I had a driver's side handbrake plate (between the shoes) on the passengers side. So the pas side handbrake came on 5mm quicker than the driver side. Flipping it over fixed the problem. Also, the pas side drum had a slight amount of trans oil in it. Took me two goes to get the right shoes, but I'm on the right track now.