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Wheel lock up

rolemin

Enthusiast
Messages
93
Location
diss norfolk
Hi
Can anyone suggest what I check first. Was out in my 1986 4gtl ,when n/s/r wheel locked for a couple of seconds. I stopped all seemed OK, went another mile, done it again, then no trouble for next 10 miles or so.
 
If you have drumbrakes maybe something get lose and jam in the drum. Can be friktion material that got lose from brake shoe etc.
Can also be a wheelbearing that is worn or badly adjusted resulting in that wheel tilting so friction material get pushed to drum or disk.
Third ting is bad old brakeline working like one way valve.
Hope you find out what is behind your troubles and give us feedback.
 
Thanks, wheel and drum off later today, strange thing was ,there was no heat from hub ,when I felt wheel
 
Has to be wheel bearing not adjusted correctly, brakes need adjusting or badly worn, seen this many times before!
 
I can't see how wheel bearing adjustment, brake adjustment or brake wear could cause a wheel to suddenly lock up and then immediately be ok again.
The "one-way" brake line phenomenon can happen if a hose has perished internally to the extent that fluid can only pass through it under pressure. The same can happen with a damaged (crushed) pipe. However, in either case, the brake would not free off as quickly as described (and anyway, it wouldn't suddenly lock up. At most it would stay on at the same pressure as had just been applied).

The most likely thing to cause a brake to suddenly lock up, out of the blue, (without the brakes being applied), is that the friction material has detached from one of the shoes, turned around with the drum and wedged in between the other shoe and the drum. It may have broken up and dislodged itself (or was released when the wheel was turned the other way: did you reverse?) and then part or all of it wedged in again a mile later. The fact that it didn't happen again in the next 10 miles might have just been luck (that it stayed in a safer position) or it could be that either it broke up sufficiently that pieces were too small/thin to cause a problem, or (in extreme circumstances) that the friction material could be worn so thin and be so far out of adjustment to the extent that there's enough gap that the loose parts don't get wedged in. (I suppose it's also possible that the second one is now also detached and so they are turning together, rather than one loose one wedging into the other fixed one).
You might also possibly get a similar effect with a broken spring: loose parts inside the drum, getting wedged in, with the added effect of a shoe that is no longer held properly in its position due to it's spring being broken.
Please let us know what you find when you take the drum off.
 
This might sound somewhat of a "curved ball", but may I ask: have you had new tyres fitted recently? I attended a Renault with an identical problem (a Clio, although it could have happened to any car) where the owner had had new rear tyres fitted. The garage had used an air gun to tighten the wheel nuts, and the resultant vibration had shaken the brake lining from the shoe, resulting in the wheel locking up and then releasing. The repair I carried out involved a new set of rear shoes all round and subsequent adjustment, but fortunately nothing more serious.
 
I can't see how wheel bearing adjustment, brake adjustment or brake wear could cause a wheel to suddenly lock up and then immediately be ok again.
The "one-way" brake line phenomenon can happen if a hose has perished internally to the extent that fluid can only pass through it under pressure. The same can happen with a damaged (crushed) pipe. However, in either case, the brake would not free off as quickly as described (and anyway, it wouldn't suddenly lock up. At most it would stay on at the same pressure as had just been applied).

The most likely thing to cause a brake to suddenly lock up, out of the blue, (without the brakes being applied), is that the friction material has detached from one of the shoes, turned around with the drum and wedged in between the other shoe and the drum. It may have broken up and dislodged itself (or was released when the wheel was turned the other way: did you reverse?) and then part or all of it wedged in again a mile later. The fact that it didn't happen again in the next 10 miles might have just been luck (that it stayed in a safer position) or it could be that either it broke up sufficiently that pieces were too small/thin to cause a problem, or (in extreme circumstances) that the friction material could be worn so thin and be so far out of adjustment to the extent that there's enough gap that the loose parts don't get wedged in. (I suppose it's also possible that the second one is now also detached and so they are turning together, rather than one loose one wedging into the other fixed one).
You might also possibly get a similar effect with a broken spring: loose parts inside the drum, getting wedged in, with the added effect of a shoe that is no longer held properly in its position due to it's spring being broken.
Please let us know what you find when you take the drum off.
Had this happen to me on Ronnie. Brake material detached from the metal backing and wedged in the drum. When i stopped the stuff fell back and the wheel moved again, and then the same thing happened. Replaced shoes and all has been well.
 
Could it be the brake pressure limiting valve?
 
I can't see how wheel bearing adjustment, brake adjustment or brake wear could cause a wheel to suddenly lock up and then immediately be ok again.
The "one-way" brake line phenomenon can happen if a hose has perished internally to the extent that fluid can only pass through it under pressure. The same can happen with a damaged (crushed) pipe. However, in either case, the brake would not free off as quickly as described (and anyway, it wouldn't suddenly lock up. At most it would stay on at the same pressure as had just been applied).

The most likely thing to cause a brake to suddenly lock up, out of the blue, (without the brakes being applied), is that the friction material has detached from one of the shoes, turned around with the drum and wedged in between the other shoe and the drum. It may have broken up and dislodged itself (or was released when the wheel was turned the other way: did you reverse?) and then part or all of it wedged in again a mile later. The fact that it didn't happen again in the next 10 miles might have just been luck (that it stayed in a safer position) or it could be that either it broke up sufficiently that pieces were too small/thin to cause a problem, or (in extreme circumstances) that the friction material could be worn so thin and be so far out of adjustment to the extent that there's enough gap that the loose parts don't get wedged in. (I suppose it's also possible that the second one is now also detached and so they are turning together, rather than one loose one wedging into the other fixed one).
You might also possibly get a similar effect with a broken spring: loose parts inside the drum, getting wedged in, with the added effect of a shoe that is no longer held properly in its position due to it's spring being broken.
Please let us know what you find when you take the drum off.
I could not get drum off as no puller handy .I have since done another 60 miles, no problem, but have I just been lucky. Waiting to get hold of new shoes, before taking to bits, in case need to replace.
 
Once you've removed the split pin and the hub nut, you could bolt the wheel back on and use it as a puller. Something similar once happened to my GTL, luckily when it was parked. When I released the handbrake, one of the rear wheels locked. It was a real struggle to remove the drum, even using the wheel as a puller, When it did eventually come off, I found that the friction material had fallen off one of the shoes.
 
After removing the drum ,the only item loose inside, was the small spring which hold shoes together at the top........very odd
 
That would be enough to do it! If the shoes aren't held tight to the hydraulic cylinder, it would grab into the drum in both directions (Known as self-servo effect)
 
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