MX5 NB - one rear wheel won't turn forwards
Discussion
Our MX-5 NB is currently on a recovery lorry feeling rather sorry for itself. The rear offside wheel will not turn when the car is in first gear/being driven forwards. The rear nearside wheel spins happily.
Strangely, both wheels will roll when the car is being driven in reverse.
I am guessing a stuck brake calliper. Is there an easy fix, or does it just require a replacement calliper?
Annoyingly I replaced this same calliper last year. Maybe it was just defective. Maybe I cocked up the fitting - but it seems like a fairly straightforward, idiot proof job. Obviously I bled the brakes.
Thanks!
Strangely, both wheels will roll when the car is being driven in reverse.
I am guessing a stuck brake calliper. Is there an easy fix, or does it just require a replacement calliper?
Annoyingly I replaced this same calliper last year. Maybe it was just defective. Maybe I cocked up the fitting - but it seems like a fairly straightforward, idiot proof job. Obviously I bled the brakes.
Thanks!
Took me a while to get round to looking at this.
Replaced the "sticking" rear offside brake calliper. Replaced all brake pads for good measure.
Problem persists.
I reversed the car off my drive and drove 200 metres down the road (forwards). Tried some super low speed braking in forwards and reverse and it worked fine. Took the car up to 20mph and braked to a standstill. Horrible grinding noises from the rear end. Rear offside wheel won't spin forward. It will spin in reverse. Rear near side wheel spins freely.
Any idea what the problem might be if it isn't the brake?!
Replaced the "sticking" rear offside brake calliper. Replaced all brake pads for good measure.
Problem persists.
I reversed the car off my drive and drove 200 metres down the road (forwards). Tried some super low speed braking in forwards and reverse and it worked fine. Took the car up to 20mph and braked to a standstill. Horrible grinding noises from the rear end. Rear offside wheel won't spin forward. It will spin in reverse. Rear near side wheel spins freely.
Any idea what the problem might be if it isn't the brake?!
Could it be knackered brake lines?
I am intrigued as to why I overhauled the rear brakes, bled the replacement calliper, tested the braking at walking pace on the driveway, then when I took it out to the road up to third gear, there was the dreadful grinding noise from the rear end (which sounded like binding brakes).
There was a mild rubbing/grinding noise from the rear end when I was taking the car up to speed, foot not on the brake pedal.
I have adjusted the calliper piston on both rear brakes (using the H4 wind back mechanism) so the handbrake locks and unlocks the brakes.
I am intrigued as to why I overhauled the rear brakes, bled the replacement calliper, tested the braking at walking pace on the driveway, then when I took it out to the road up to third gear, there was the dreadful grinding noise from the rear end (which sounded like binding brakes).
There was a mild rubbing/grinding noise from the rear end when I was taking the car up to speed, foot not on the brake pedal.
I have adjusted the calliper piston on both rear brakes (using the H4 wind back mechanism) so the handbrake locks and unlocks the brakes.
I very much doubt its a brake line issue.
Might be worth taking out the rear pads completely and seeing if the car wheels will rotate both ways with the rear jacked up? Maybe try it jacked up with the pads in first, then remove them and see what happens.
I'm thinking diff issue, the grinding noise being the internals of the diff, if you prove this to be so, an diff oil level check and then change would be my first port of call.
Might be worth taking out the rear pads completely and seeing if the car wheels will rotate both ways with the rear jacked up? Maybe try it jacked up with the pads in first, then remove them and see what happens.
I'm thinking diff issue, the grinding noise being the internals of the diff, if you prove this to be so, an diff oil level check and then change would be my first port of call.
So the issue was that the top bolt in the bracket holding the rear OS brake calliper to the chassis was missing. The bottom one was there. This meant that, when I pressed the brake pedal with the car moving, the brake caliper pivoted forwards, locking against the wheel hub. This prevented forward movement, yet allowed reverse movement.
Fit a bolt to the missing hole...and lovely smooth braking!
Fit a bolt to the missing hole...and lovely smooth braking!
Sounds like somebody didn't do their job properly last time the rear brakes were done, not only should that bolt be tight enough that it doesn't come undone, it would normally be threadlocked as well. Good job it wasn't the bottom bolt missing, the calliper could have jammed against the rear wheel and locked it at whatever speed you were travelling . Perhaps a good idea to avoid that garage in future!
Gassing Station | Mazda MX5/Roadster/Miata | Top of Page | What's New | My Stuff