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edlithgow
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PostSubject: Do self-adjusters suck?   Mon Jul 13, 2015 1:01 pm

Just had a classic example of "If it ain't broke" replacing the functional LHS brake shoes following the replacement of the faulty RH ones, because of course you buy,and I suppose you're supposed to replace, both sides. Faulty RH side was a fairly easy fix, functional LHS a real pain.

Anyway, this prompted reflection on self adjusting brakes. On my bangers, I always seem to have to hammer the drums on and off, the adjusters quite often don't seem to work, and when they do they often seem to drag.

Long time since my last manual adjusted drums (I think on my Lada) but I remember them fondly.

Is this just rose-tinted-retro?
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Justwatching
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PostSubject: Re: Do self-adjusters suck?   Fri Jul 17, 2015 9:59 pm

Not sure if I've ever had manual adjustment drums (though effectively, that's what they all are as the auto-adjust doesn't work properly). When did auto-adjust become main stream, do you know?

I think the principle is sound. For one reason or another, the implementation is a different story. I think neglect plays a big role in adjuster malfunction, though auto-adjustment does invite neglect, does it not?


Last edited by Justwatching on Fri Jul 17, 2015 10:00 pm; edited 1 time in total (Reason for editing : Can't speel)
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edlithgow
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PostSubject: Re: Do self-adjusters suck?   Sat Jul 18, 2015 2:48 am

My first few cars (eg Triumph 1300, Marina, Lada) had manual adjusters.

On the Lada (Mk 1, they probably succumbed to Western Decadence on the Mark II) it was an eccentric cam inside the drum, with a biggish (maybe 10mm) bolt head adjuster on the outside of the backplate. Spin the drum (or wheel if you'd left it on), adjust with spanner till it drags, back off a little. Wasn't rocket science (Well, maybe it was similar to Soviet rocket science) and got the job done quickly and accurately.

I suppose it could have given trouble, since I THINK the cam was held in place by friction, and I don't know if this could be adjusted or locked if it got loose, since it didn't.

I think the others were similar but not quite so robust. I don't remember them so well, but I would if they'd ever given me any trouble.

My first exposure to automatic adjusters was on a newish Renault 5 Campus. The gadget was made of what looked like phosphor-bronze alloys (presumably to mitigate the effects of neglect/corrosion you mention above)

It was absolutely beautiful, (a mechanical wizard friend of mine who saw it opined that it probably cost as much to make as the rest of the back suspension), and it absolutely would not work.

A negative benefit of the exotic alloys was that it was fairly soft, so tended to get damaged by manual adjustment with a screwdriver, but since it didn't work worth a damn anyway, this was only an aesthetic annoyance.

Later examples I've had have been less pretty, but equivalently useless.

I take your point about neglect probably being a factor, since the less exotic materials suffer from corrosion, as on the Daihatsu, but if you take them apart, clean them up, and lubricate them, (I've been using PTFE tape as a lubricant supplement this time around, which I havn't tried before) and they look OK but STILL don't seem to work, it starts to look like they're broken-by-design.

Or its me.

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Justwatching
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PostSubject: Re: Do self-adjusters suck?   Mon Jul 20, 2015 12:11 am

How often did the manual adjustment drums need adjusting? Once a year?

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edlithgow
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PostSubject: Re: Do self-adjusters suck?   Mon Jul 20, 2015 10:35 am

Hard to say. Since they were easy to fiddle with, I probably fiddled with them a lot more than they needed (especially with low miles), probably whenever I had the wheel(s) of the ground.

This contrasts with self-adjusters which are a royal PITA to manually adjust so get left alone, not so much because automation breeds laziness, more because pain breeds aversion.

Lada had a manual timing chain tensioner too. 30 second job, though my pushrod engines beat that by not having a timing chain.

Progress?
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Justwatching
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PostSubject: Re: Do self-adjusters suck?   Fri Jul 24, 2015 11:22 pm

Come to think of it, they still don't work well when dirt/rust free. I always have to manually adjust them after a brake rebuild. If the mech worked properly, they'd adjust themselves. No amount of working the brakes seems to do it.
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edlithgow
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PostSubject: Re: Do self-adjusters suck?   Sat Aug 01, 2015 11:22 am

Was in the Toyota Museum in Nagoya earlier this week, where they had a lineup of bare chassis giving an unusual view of unusually clean brake mechanisms across the years.

IIRC the last Corolla that looked like it had manual adjusters was a 1980, later than I'd have guessed. It was a slotted screw with a locknut, so my recollection of the Lada one not being lockable might be at fault (or the Toyota is better, which isn't that hard to believe, even for a Lada fan like myself).

It also looked easy to do.
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Justwatching
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PostSubject: Re: Do self-adjusters suck?   Sun Aug 02, 2015 11:16 pm

1980 is a little later than I'd have expected. I'm sure my '77 Capri had auto-adjusters. Perhaps Toyota knew they didn't work, and hence the late implementation.

A thought - are all drum brakes not defacto manual adjustment given that the auto-adjust doesn't work properly and they are manually adjustable with a screw driver anyway?
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edlithgow
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PostSubject: Re: Do self-adjusters suck?   Mon Aug 03, 2015 12:39 am

Justwatching wrote:


A thought - are all drum brakes not defacto manual adjustment given that the auto-adjust doesn't work properly and they are manually adjustable with a screw driver anyway?

You could argue that, or you could argue that they sometimes aren't adjustable at all, since they can be F-ing impossible to do manually with the drum on and the car on low axle stands.

I havn't so far succeeded in doing the Skywing that way, thoughI have succeeded in losing the little rubber plugs in the brake back plates.

It might be OK from a pit or lift with one of those special cranked adjuster-thingy tools, which should be fairly easy to make.

They look like some bicycle tyre levers, of which I have a few, somewhere...
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edlithgow
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PostSubject: Re: Do self-adjusters suck?   Wed May 18, 2016 1:22 pm

I actually bought some special adjusting tools, the very existence of which is industry confirmation that automatic adjusters aren't automatic and don't adjust.

They were fairly expensive (about a tenner, a lot for a bicycle tyre lever analogue), and they didn't help.

I am a mug.

I find it very difficult to achieve anything through that tiny window. I've had my rear drums fairly lose since I last worked on them, but felt I needed to tighten them up for inspection.

The procedure I used was:-

1. Take drums off and grind the inner edge with a stone in power drill, to remove any lip, to make it easier to get the drum on and off with the brake shoes extended.

2. Put a cable tie through the ratchet pawl lever (I made that up. I don't know what its proper name is) in which there is a convenient hole. Thread the thin end of the cable tie through the tiny window in the back of the brake. Cut off a ratchet block from another cable tie and slide this ratchet block along the cable tie until its almost flush with the hub back plate.

3. Slide some needle nose pliers between the second ratchet block and the back plate. This wedge action pulls on the cable tie and moves the ratchet arm off the self adjusting toothed wheel.

4. Adjust the toothed wheel to be as tight as possible while still being able to get the drum on. This requires some trial and error. I used a larger cable tie to protect fingertips while turning the wheel. The ridged surface of  the cable-tie gives it grip.

It MIGHT be possible to develop this method to allow fully manual adjustment. I have some ideas for this but I don't know if I'll find the time to try them.

5. When the drums are back on, release the cable tie holding the ratchet pawl arm away from the toothed wheel. Apply the brakes and handbrake a few times.

6. I've seen it claimed that the self adjustment only works in reverse, and with fairly firm braking. I've also seen it claimed that it works while turning in reverse, with firm braking. Its isn't obvious to me why either of these claims would be true and I don't think I believe them, but I tried it anyway.

The brakes (notably the handbrake) are tighter now. Its too early to say if they are successfully self adjusting.
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Justwatching
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PostSubject: Re: Do self-adjusters suck?   Fri May 20, 2016 9:11 pm

edlithgow wrote:


I am a mug.


Glad I aint the only one.

Not sure I follow what was going on the description you gave, but the brakes work now (I got that bit), so that's good.
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edlithgow
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PostSubject: Re: Do self-adjusters suck?   Sun May 22, 2016 5:30 am

Short version :

1.Grind off any lip on the drum
2. Fit a cable tie pull on the ratchet arm to reversibly hold it disengaged hands-free.
3. Adjust it with the drum off to JUST allow the drum to go back on.

I'd have taken pictures, but I lost my camera.
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