Need help diagnosing an issue

Questions and Answers
1

Need help diagnosing something.

Got a m100, just developed a slight thudding in all the pedals.

Happens when engine is in high revs, if I change gear it goes away till revs are high again.

As the car is going it’s not there but as rpms are building the slight thudding in pedals will start and thudding will speed up, in a consistent pace.

For example,

D. , D. , D. D. D. D DDD

Ive changed the front brakes, disc and pads, I’m going to do the rear shoes and cylinders today. It’s lowered all round also.

Any help would be great.

2

Is it just in the pedals? And at what speed does it occur? If it’s at any speed but only when you rev high it might be engine mounts. If it happens at a higher speed than it might be your tires.

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3

Hey mate thanks for reply.

So every gear that a high rpm/speed when you change to the next gear, it happens in every gear, you can feel the thudding build up with the speed.

Some things I’ve noticed;

When it’s thudding at high speed, I’ll clutch in and engine will drop rpms, but thudding is still there until I slow down and the thudding slowly dies off

Tonight I did my rear brakes, front are new too, no change, but I took her for a spin and decided to check my air in tyres, the tires were 22 psi! I was shocked, I filled it up to 36 cause U wanted to see if it would change and it did, the thudding was significantly quiet but still there, the car also has aftermarket wheels.

Not sure what’s going on, I still have the old steel rims so I’m thinking about swapping them over to see if it goes away?

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4

Okay so when you press the clutch the thudding is still there even if the rpm drops. That would indicate that its not something with the engine mounts etc but rather something with the wheels.

So yeah try changing the wheels back to original if those rims still have tyres. Maybe a wheel weight fell off the wheels you run now of maybe the rims are bend. Could even be the tires that you run now etc etc.

Let me know if it works!

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5

Have you checked if your tires are cupped this may cause the sound your describing

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6

Thanks for the reply .

The thudding or slight knocking is still there when clutching in but as the roms drop or vehicles slows down the slight knocking speed slows with rpms then under 2.5k rpm goes away until increase speed and it’s bsck

7

Hey i thought i replied ages ago, had her on stands, took wheels off, still there.