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MG MGA - Brake and Clutch Issues
|I had a new steering rack installed, along with two completely rebuilt swivel pins. All new bushings in the A-arms as well. This is a 58 A roadster with drum brakes all the way around and single master cylinder.|
The brakes were bled and adjusted, and everything was reassembled. When I picked the car up, I could not believe the huge difference in the steeing and handling quality of the car. Truly amazing!
WIth that said, here's my problem. The front brakes are rubbing very loudly when braking, especially noticable when the pedal is depressed firmly. I suspect it may be the leftt front wheel. If pressed very firmly, the car wants to pull to the left. It comes close to the feeling of locking up the brakes. Prior to the work described above, the brakes were never an issue.
Here's another odd thing. In addition to the rubbing brakes, when I down shift from 3rd gear to 2nd, there is a similar grinding/rubbing noise at the friction point of the clutch. This is not a gearbox clash, but rather sounds like the loud brake rub. There is no issue with the cluch when upshifting.
Any suggestions as to what to check would be appreciated.
Well, I'll take a stab.
Tha brakes, I imagine they had everything taken apart. There may be a ridge of rust on the rim of the drum where the brake shoes never rub. When re-assembling it. the shoes are not in their original homes and are rubbing on the ridge of rust, making the grinding noise. It may quiet down in time after the shoes either grind the rust down or take the shape of the drum. Barring that maybe they have reassembled something wrong, brake shoe not located properly etc. I would bring it back to them and take them for a drive.
If you want to do it yourself or have them do it, it would not be a bad idea to pull the offending drum off and have a look.
As for the clutch noise, I don't have a clue. Since it is just from 3rd to 2nd is strange unless the hydraulics are not bled properly, but you didn't mention any other issues with the clutch action. It may be in the gearbox.
I had another thought, far fetched maybe, but maybe the wheel bearing on that side is not shimmed or seated properly and it is the same noise you are hearing. If there is too much play, maybe the wheel is shifting side to side when you apply the brakes and maybe does it when you downshift also. To check it is easy. Jack that side up and facing the wheel push in and out and twist side to side also to check for play. It shoud be minimal, just a few thousandths of an inch (without looking it up). If it is very loose, don't drive the car until you take things apart to check it out, unless you want to see what a 3 wheel car handles like. :>)
|Thanks for the suggestions Ralph. |
Interestingly, when they pulled the front hub to remove the stub axle and swivel pin assembly, the wheel bearing on the left side was frozen in place on the axle. They had a heck of a time removing the bearing. Although the swivel pins were replaced with rebuilt ones, including a new stub axle, they may have used the old wheel bearing. Would this have any affect on proper seating when the hub was reinstalled?
|Possibly. Maybe the bearing was damaged? But also there are shims that go in there to get a proper fit on the bearing, to achieve the correct end float. Thus the few thousandths end play (float). Too tight - the bearings will heat up. A new stub axle would likely require new shims. Did you check the wheel for play? We're leaving for Reno (MG 2011) in the morning, and I'll try to check before we leave. If you don't hear from me its not because I an ignoring you!|
|There are no shims in the front wheel assembly, only a solid spacer.|
|This is a wire wheel car, so the hub is splined. Not sure there are shims or spacers in this application.|
|Doesn't matter, WW or disc, there is just a spacer on MGA hubs.|
|Just had an Aha moment! |
I pulled the drum on the suspected left front wheel, and found that the shoes were cocked at an steep angle to the drum face. Upon further inspection I found that the forward hydraulic cylinder would open when the pedal was depressed, but would not return to the closed position when the pressure was released. Also found that cyclinder to be squirting fluid under pressure.
I believe this caused the brake shoes to engage the drum very unevenly at the rear cyclinder, causing the grinding noise. I plan to replace both cylinders, and hopefully this will solve the problem.
This thread was discussed between 04/06/2011 and 05/06/2011
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