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Brake problems

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H

higgins

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My 100/6 longbridge model has brake drums all around.

I recently had the front drums turned and also installed new brake pads.

Since then, although the car brakes, it vibrates heavily.

I've rechecked everything now for the third time, and although in the beginning the vibrations are less, as soon as the brakes heat up the problem is as before.

I'm at a loss , please help :bow:
 
How did you bed the brakes?

Bedding refers to braking in the shoes (or pads) by depositing a very thin amount of brake material onto the surface of the drum (or disk). MOSS has posted a procedure on their web site but the most common approach is the 30/30/30 method.

Simply put, the 30/30/30 method consists of 30 stops from 30MPH with a 30 second (foot off the brake) between each stop for cooling. Hard stops and standing with pressure on the brakes will deposit more material on that spot and produce an inconsistent coating and vibration.

Take a look at the MOSS MOTORS article https://www.mossmotoring.com/bedding-in-y...rDriveSaleBump1 . It presents a good procedure and has a more complete explanation of the process and how to correct the uneven coating I believe may be causing your vibration.

Good luck,
Ray (64BJ8P1)
 
Sounds like the drums have distorted. They my be too thin after being turned out.

If new ones are available I'd buy them.
 
Hi Rac68

I did bed them, but not according to the 30/30/30 method.

However, the vibrations are really strong and so I've also thought, like EV2239, that they might have thined out.

What would be the normal thickness for the drums?

Unfortunately, new drums don't seem to be available anymore (unless of course someone out there knows where)
 
Whenever you use new drum pads they need to be made to fit the inner surface of the drum. Take them to someone who can re-arc them. The problems should go away.
 
Since you had bedded the brakes with no remedial success Riches suggestion is the next I would follow…however, I have never arched my pads and experienced any negative issues.

I had noticed you indicated that the vibration would increase when the brakes/drums increase in temperature. This seems to me an indication of uneven expansion of the drum/s which is a further possible indication of uneven wall thickness.

To be clear, is the vibration occurring only when applying the brakes, all the time, or at specific speeds?

If only when the brakes are applied, I then suspect that the drums are unevenly warping and getting out-of-round. If this is the case then I suspect arching the shoes will not solve the problem and only replacing the drums will satisfy.

If the vibration is present at all speeds with or without the direct application of the brakes, then I think the issue may sill be caused by uneven drum expansion that is causing the drum to become out of balanced. In this case, the solution is still drum replacement but may be diminished or eliminated by balancing the drums.

Last, if the issue is experienced at specific speeds, then I would definitely check the balance of the drums before replacing them.

Hope this helps,
Ray (64BJ8P1)
 
Hi Ray,

it only vibrates when braking at any speed.

If I brake from a higher speed, especially if I need to brake quickly, the whole steering columns vibrates strongly up and down and I practically need to concentrate on holding the steering wheel in my hands.
 
So, as I understand, the vibration is substantial when the brakes are applied and at temperature. Also, should I conclude from your response that there is no vibration when just cruising and not applying the brakes? Have you moved the drums to different wheels and has the vibrations continued and in a consistent way? After re-bedded? I am assuming the brake shoe material is not causing the problem but this may not be true as I had experienced new disk pads that caused stopping issues (this was easy to identify as reinstalling my old pads eliminated the problems).

My suspicion is that only one drum has a problem but I keep thinking that the drum/s are out of round with respect to the shoes and could have been caused by the following:
1. One or more drums may have not been properly centered when cut. I would take them back to the cutter and have him recheck them for centering and roundness.
2. One or more drums have irregular wall thickness and are expanding to an out-of-round situation when heated. You may be able to detect this condition with a micrometer but I would, again, go back to the cutter.
3. One or more sets of shoes are out of round with respect to the drums which. In this case you could resolve this condition by arching the shoes.

As mentioned, I would try to identify which drum or drums are causing the vibration by systematically moving the drums to different wheels. Since the steering wheel is bouncing, I would start by exchanging one front and back drums on the same side. It will be difficult, or even impossible, to detect the problem drums in this manner if multiple drums are problematic but, as I suspect, can help if only one is in error. I anticipate that the steering wheel vibration will be greatly diminished if the problem drum/s is isolated to the rear wheels.

Good luck,
Ray (64BJ8P1)
 
:iagree: with all Ray says, you definetly have an out of round drum somewhere. I've always approached this type of problem by starting with the simplest, easiest to fix solution first. I'd first put the front up (It sounds like you have a front wheel problem) on jacks and spin each wheel by hand to check for any out-of-round condition. With that much vibration you might just "see" something. Next I'd have someone gently apply the brakes while spinning the wheel, again looking for anything unusual. With the brakes applied check that each front wheel is braking equally on each side by forcibly try and turn the wheel.

You mention only vibration, but does the car veer to one side or the other as well?
 
hi Ray

the rear drums are new alfin and worked fine without a problem. After running them for about 2 weeks I had the front ones turned and then the problem started.

I've already changed the left front drum to the right side and vice versa. In the beginning the vibrations were less but now they are definitely bad .

I needed to change the pads as they were well worn and even splitting. while doing so I decided to have the drums turned so I can't really tell if it could be due to the pads I still have the old ones and could try putting them back on to see what happens.
 
hi Johnny

that's the strange part, the car holds its track. when I press really hard on the brakes they even lock up after a certain time.
 
Did you replace or rebuild the wheel cylinders as well?

If you did, you might want to check that their operating correctly by removeing the wheels, and the outer drums, and visually check that each wheel cylinder is working together with similar travel. Of course you have to have an assistant to operate the brakes while you're watching.
 
Just to let you know that I put on a new second hand set of drums, as brand new ones no longer seem to be available, and now the car brakes like new.

Many thanks to you all for your advice,
 
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