Howling Brakes

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This topic contains 10 replies, has 6 voices, and was last updated by  newkitman 12 months ago.

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  • #302346

    johnsimion
    Participant

    @johnsimion

    The front discs on my car are apparently are okay now but for the umpteenth time the rear drums have re-developed the squealing/howling sound and it is just unbearable.  I just got back from a 10-mile ride which I cut short because my car was so embarrassing.  I was driving through a residential area and had to stop for three nearby school buses.  My brakes were FAR louder than the buses and the little children all turned around to see where the horrible sound was coming from.  This is not the kind of attention I bought the car for.

    I am sick and tired of this bullshit.  The shoes were first replaced by Mechanic #1.  Much later (but without much driving) in a quest to eliminate the squealing, Mechanic #2 cleaned and lubricated the entire system (although he said it wasn’t really very dirty) and checked everything and said it was okay.  He did sand down the shoes and chamfer the edges that he said usually stopped squeaking.  That worked for about 10 miles, then it started again.  I took it back and this time he showed me where the shoes in the car had hard spots where they looked shiny versus the rest of the shoe.  He said the drums were okay, which made sense to me since the car stops straight and without pulsing — albeit with horrible noise — so he replaced the shoes and took it for a long test drive and announced the problem was solved, and it was solved until most of the way of my 20 mile drive home, whereupon it began making noise albeit softly.  Since then it’s gotten progressively louder and louder.  The last two times I’ve been out it has squealed like a pig and today was the worst it’s ever been.  And all this has developed within 100 miles.  If I lightly touch the brakes, as you do when you slowly pull up to an intersection, it’s absolutely horrible.  If I press harder but gently, the squealing continues.  If I press with a sudden and hard action, it is actually quiet but that also skids the tires.

    Right now it’s all but undriveable with this horrible sound.  What’s next, another $500-600 to put on rear discs to go with the front discs?  At least the front discs finally stopped singing after three or four trips to the mechanic.  But for all I know the axles may be twisted or something and nothing is going to solve this.  I’m sick and tired of plowing cash and a lot of time into the bottomless chasm for no discernible benefit.  Right now what I have is a very expensive garage ornament.

    • This topic was modified 1 year ago by  johnsimion.
    #302372

    edsnova
    Participant

    @edsnova

    Interesting problem. I’d never heard of rear brakes making so much racket. Something, for sure, ain’t right.

    One thing to check is the inside edge of the shoes, to see if they are rubbing on the backing plate. If they are, a little Never-Seize or brake anti-squeal paste should get it. Keep it off the working faces of the shoes and drums. If you get any on them, hit them with some brake kleen.

    The other possibility—less likely in your case because the brakes were just serviced and you say there’s no pulsing—is that the drums need resurfacing. I’d consider doing that anyway for like $10 and scuffing the pads again with some 80-grit paper.

    Make sure the shoes are back in the right way. Get a manual or the “For The Compleate Idiot” book and look at the drawings. Make sure all the springs are right & nothing’s twisted or interfering with any other parts down in there.

    Then adjust them properly with the star wheel. You want to turn the adjusters till they spin free, then tighten like 2-3 clicks so the wheels just barely drag.

    After that, do this: bed the brakes.

    Take the car out and speed it up to 50 or 60 and jam on the brakes for a panic stop. Do it 5 or 6 times. Then drive slowly home braking as normal.

    #302374

    royal
    Participant

    @royal

    Ed has some good advice.  My guess is that the noise is from the springs which are contacting the brake drum when the brakes are applied.  They may be on backwards….or perhaps they are the wrong springs.  If you don’t have an “Idiots” book, it is a worthwhile investment.

    Do the brakes squeal when you apply the parking/emergency brake?  Try to stop, only using it.  What happened?

    #302401

    johnsimion
    Participant

    @johnsimion

    I took some of Ed’s advice today:  “Take the car out and speed it up to 50 or 60 and jam on the brakes for a panic stop. Do it 5 or 6 times. Then drive slowly home braking as normal.”  I also did Royal’s test:  “Do the brakes squeal when you apply the parking/emergency brake?”

    First the parking brake.  I used only the parking brake to slow me as I backed out of my driveway and also used it solo to stop me the first couple of times going straight while the brakes were cold.  Not a sound, although using my parking brake to stop is about as effective as skidding my shoe on the highway.  It definitely “applies” and there is pressure to it and some effect, but not enough effect to hold the car on the 15 degree incline of my driveway.  Anyway, the point was, no sound.

    Then the panic stop test.  Pulling out of our subdivision (after the parking brake test) over to my chosen street for the test, it was still howling at every stop sign.  I pulled onto my chosen street* and did the first panic stop from 50 mph and never heard anything (one limitation is that the front discs tend to lock up and slide, so I stopped with as much pressure as I could apply without locking them).  Did this perhaps a dozen times and never once heard a sound.  Felt the rear drums, which were really hot by then, which I figured to be a good thing.  Drove home very moderately and never heard another sound.  I even turned off the engine and coasted just to be sure.

    As well as this went, I am mindful that the previous time I took the car out the brakes were quiet if I applied heavy pressure but they howled at light pressure and low speeds.  I’m also mindful that I thought the brakes were fixed twice before when I left the mechanic’s shop and started howling before the end of the 20-mile drive home.  I will go out again tomorrow or Wednesday and try it again at low speed with cold brakes, then take it on another 20 mile trip in stop-and-go city streets.  If it’s still quiet after those tests, then maybe the problem is truly solved.

    Regardless, thanks for the advice.  If the problem still doesn’t go away, I’ll print out this thread and give it to the mechanic to check all the internal stuff.

    *  This was a straight residential street with a 35 mph speed limit and no stop signs; however, there are very few houses and almost no traffic.  Still, it must have really looked weird to the residents as there can’t be too many 1952 MG TD Replicas doing panic stops there.  Either nobody cared or I got back home before the cops were called.

    #302403

    royal
    Participant

    @royal

    John, Good……I guess.  I never feel very good about problems that just go away without my having figured out what was wrong.  I still say that it sounds to me like there is something rubbing on the inside of the drums – maybe a spring or something else due to incorrect installation of the shoes.  A really good close visual inspection, looking for shiny parts, that have no excuse for being shiny, would likely (hopefully) reveal the problem.

    Good luck, Roy

    #302404

    kentt
    Participant

    @kentt

    Also sounds like your parking brake is not adjusted or working correctly. They should definitely hold the vehicle on as steep an incline as you’d want to drive it.

     

    You should be able to hold your thumb on the button and execute a “moonshiner’s turn” – lock up the rear brakes and with a quick turn of the steering wheel have the rear of the car swing around. You can purchase dual brake levers to steer the vehicle – used commonly on sand rails and buggies…

    Early FF TDr on 69 VW pan
    Slowly coming back from the ashes...

    #302425

    johnsimion
    Participant

    @johnsimion

    Took the car out today for 30 or 45 minutes for a followup test.  Utter silence except for minor squeaks two times, and they were more like an emasculated mouse than a Screamin’ Eagle.  At the end of my test, I repeated the 50-0 panic stop exercise several more times, then drove a little further and the mouse remained silent again.  I’ll do another test over the weekend, but my “take” on the brakes right now is that there is or was something on the drum or the shoe that was causing the sounds, and that the repeated panic stops have worn it away so that it’s no longer pestering me.  Perhaps my previous symptoms just meant my brakes needed “bedding in” and now they’re getting to be bedded in?

     

    Certainly the car stops well enough.  The only problem with stopping is that the front discs are so powerful that the tendency to lock up actually lengthens my stopping distances.  In the long run I plan to make a removeable concrete-and-lead “brick” to fit into the space now occupied by the jack under the hood.  The weight I’ve already added has helped the discs get grip, and the additional weight of the “brick” should make them even better.  The weight should also help neutralize the balance and reduce the tail-wag caused by all that weight at the rear (not that it doesn’t handle well — it corners pretty darned good already but I’d still accept improvement).  I can find another place to store the jack, so that’s not a problem.

    #302426

    edsnova
    Participant

    @edsnova

    Great news. Please update on the stopping/lock-up when you add weight.

    The other option is to buy and install a proportioning valve and bias the rears a little until they all lock at the same time.

    #302440

    royal
    Participant

    @royal

    Yes, a proportioning valve might do the trick.  Do you know that you have the right master cylinder installed?  Also, if your rear tires are better than the fronts, this may cause the fronts to lock up first…..or the rears need to be adjusted ….or possibly the rear brakes need to be bled again (assuming you have a split system).

    I really don’t like the idea of adding weight (yet).

    #302441

    kall
    Participant

    @kall

    Sometimes a bit of “history” can make understanding our troubles a bit easier, I hope.

    Until the 70’s a good brake job included “shaping” the new shoes to match the drums.  This was done on a sanding fixture which removed high spots so the shoes would have full contact immediately rather than having to break in.  Unfortunately this process released clouds of asbestos-laced dust throughout the shop and probably led to premature lung problems in many mechanics.

    “Bedding in” would work unless:

    • the problem was an out of round drum
    • the high spots became glazed before they wore down
    • the customer couldn’t understand why his new brakes didn’t work better than his old ones.

    Once this hazzard became known, shop owners stopped shaping brake shoes and instead more carefully checked and turned brake drums to factory standards for trueness.  Hopefully, shoe manufacturers upped their standards so that their replacement shoes exactly matched the freshly-turned factory-spec drums.

    Our donor cars predate this transistion and so getting a good fit between old and possibly distorted drums becomes more difficult unless the drums are properly remachined and the new shoes are up to par.

    Just a part of the joys of restoring old cars.

    • This reply was modified 12 months ago by  kall.
    #302450

    newkitman
    Participant

    @newkitman

    I remember when I had my Ford Pinto, yes I ownef a fatigue green early 70s Pinto, it cad a rubbing strip on the calipers. When the pads worn down to minimum level the strip would contact the rotorand squeel lo ike a pig. That was time to change the brake pads and turn the rotors.

    Allen Caron
    VW based 53MGTD - "MoneyPenny"
    "If one thing matters, everything matters" - from the book The Shack

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