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Graunching after replacing front brakes

Posted: Fri Jan 22, 2016 4:39 pm
by russminor
Ive recently replaced all the brake wheel cylinders on my 71 Traveller after the fronts seized.
I also replaced all the shoes with mintex plus the small link pipes on the back of the front brakes.
Not only have I had a devil of a job getting a hard pedal without too much travel (bled with assistant 4-5 times) and still excess travel but I now have a strange graunching noise from the nearside front brake at slow speeds.
I've owned a variety of minors for 25 years and have changed brakes on many of them without problem and all parts used were Lockheed OE.
I have assumed the excess pedal travel may be due to shoes not bedding in yet and have been driving around using the brakes excessively to try and rectify this- there has been a slight improvement in performance though not to the extent I would anticipate.
Pumping the pedal doesn't produce any harder feeling so I don't think there's air int he system and therefore it must be adjustment, which hopefully will fix itself when shoes and drum are the same shape!
The main problem is that the NS front wheel has that graunching noise - I say graunching because its not really grinding, its only when the brakes are applied, seeminly at slow speeds, and is a cross between grinding and creaking, occurring in time with the rotation of the wheel.
Only the NS wheel is doing it. It's bizarre and I can't work out what would be responsible.
Perhaps someone else has experienced this?

Re: Graunching after replacing front brakes

Posted: Fri Jan 22, 2016 5:11 pm
by aupickup
maybe wheel bearing

Re: Graunching after replacing front brakes

Posted: Fri Jan 22, 2016 5:14 pm
by russminor
Thats an interesting theory - do wheel bearings have a habit of showing up under braking?

Re: Graunching after replacing front brakes

Posted: Fri Jan 22, 2016 5:22 pm
by aupickup
if they are worn maybe

Re: Graunching after replacing front brakes

Posted: Fri Jan 22, 2016 5:57 pm
by panky
Are the return springs on the correct (back) side of the shoes, if not they could be pulling the edge of the shoes onto the drum

Re: Graunching after replacing front brakes

Posted: Fri Jan 22, 2016 7:39 pm
by bmcecosse
My money too is on a return spring problem....

Re: Graunching after replacing front brakes

Posted: Fri Jan 22, 2016 10:13 pm
by russminor
I'll look in the morning - thanks for those suggestions

Re: Graunching after replacing front brakes

Posted: Sat Jan 23, 2016 9:20 pm
by russminor
A little update. I dismantled the brakes again and found the springs to be int he right positions - on the rear of the shoes. Nothing else visible out of place. No evidence of any rubbing of springs on wheel cylinders etc.
Just took it on 250 mile round trip - much of the way at 70mph on motorways - braking strong and balanced from top speed when needed - however as soon as it was back to round town driving the grinding/rubbing/graunching returned during the last part of braking, so probably below 20mph to zero.
Could it be a result of the drums previously being overheated and now causing the noise with new shoes? I cant think of any other explanation. There is no sign of oval drums but i suppose that could cause a noise to occur at slow speeds?
What is the current thinking on new drums - I usually buy spares from ESM and they list UK produced drums. I realise there are members who have posted saying the quality of replacement drums is dubious - however at some point the hard materials of modern shoes are surely going to mean we will all have to invest in new drums eventually as they will be worn away at a greater rate than when using the original asbestos shoes? - therefore it is important to find a source of well made new drums isn't it?
Any recommendations?
Thanks
Russ

Re: Graunching after replacing front brakes

Posted: Sat Jan 23, 2016 10:57 pm
by bmcecosse
I seriously doubt it is anything to do with the drums. Is it just one wheel that makes the noise ? Try swapping the drums side to side. There have been reports of 'problems' with some of the new drums.... I doubt too if drums wear any more with non-asbestos linings - very possibly the opposite I think!

Re: Graunching after replacing front brakes

Posted: Sun Jan 24, 2016 2:03 pm
by minor65
I fitted mintex shoes and Lockheed cylinders to my grey minor 2 years ago and since last autumn it has developed exactly the same noise as you describe. I intend to remove the front drums again for a check. But as the car isn't going to be out until march theres no panic.

Re: Graunching after replacing front brakes

Posted: Sun Jan 24, 2016 2:06 pm
by minor65
My drums were new and reskimmed. I am confident the springs are correct. And as the noise is only recent i am putting it down to the shoes. But I'll recheck everything again.

Re: Graunching after replacing front brakes

Posted: Sun Jan 24, 2016 5:36 pm
by liammonty
For what it's worth, I fitted Mintex shoes to mine, after being disappointed with the Willow ones that were fitted, and they are excellent.

Is the noisy wheel hotter than the other wheels after a run? If it is, that would confirm the shoes aren't retracting fully. This could be due to other issues as well as the return springs, such as a collapsed flexi hose to that wheel, or as in my case, a dodgy master cylinder.

Re: Graunching after replacing front brakes

Posted: Sun Jan 24, 2016 7:49 pm
by russminor
interesting minor65. So it cant necessarily be my drums then. Are mintex harder than other brands? maybe that could be the cause. The shoe materials now would be harder than the asbestos the drums were designed for. Maybe there's a variation among manufacturers?

Re: Graunching after replacing front brakes

Posted: Sun Jan 24, 2016 7:50 pm
by russminor
Liam - thanks for that - i'll investigate however the noise appears to only be when pressure is applied to the brakes. It may be that you are suggesting a hotter drum temp, if the shoes were dragging, could cause a different response on one side. I'll see if that is the case.

Re: Graunching after replacing front brakes

Posted: Sun Jan 24, 2016 8:23 pm
by minor65
In my case the brakes are not binding. Always cold after a run.

Re: Graunching after replacing front brakes

Posted: Sun Jan 24, 2016 8:26 pm
by bmcecosse
You sure the noise comes from the brakes - and not from the suspension?

Re: Graunching after replacing front brakes

Posted: Mon Jan 25, 2016 12:40 pm
by john newton
are the leading edges of brake shoes filed down to a taper,no more than half an inch of shoe. regards john newton...