T27 Weird Thump

[MikeEH]

Had the T27 a few months, replacing my T25, and I've been experiencing strange thumps at the front end that were not apparent on the T25. First noticed it when I reversed into the turning area at the end of my slightly sloping cul-de-sac, I accelerated a little too much, but still going slow, I got a thumping sound from the front reminiscent of axle !Removed!. If I'm gentle it's ok. Sometimes if I accelerate away from stationary in first gear, in an un-gentle manner but not speeding, I get the same thing. Two days ago as I was patiently waiting forever to come out of my local petrol station onto a main road, there was a suitable gap in the traffic coming up so I decided to shoot out. If I did, all of a sudden the axle !Removed! type thumping started then a single huge thump that sounded like someone under the bonnet hitting the bulkhead with a very, very heavy rubber mallet, at which point the electrics went out - headlights, dash lights, built-in satnav went off and engine stopped for a split second then all came on again, engine kept going and away I went wondering what the heck happened. I daren't accelerate more than gentle in first gear anymore in case the thumping starts and reversing makes me quite wary. As a test I can even floor the accelerator in any other gear without any problem. Wheels are balanced perfectly as no steering shake right up to 70mph plus, front springs seem to be intact and shocks not leaking. Any ideas please?

[paul9]

I would have been suspecting the coil springs. Sometimes they fracture in places where it is hard to tell that they are cracked. Also worth checking your engine mounts.

[mrfixer]

I would first of all check the engine mounts...

[MikeEH]

Thanks for replies.

Car's going into my friend's garage on Monday...I hope he finds something....

 

[MikeEH]

Anyone know why a word mentioned twice in my original post has been removed? It was a descriptive term for axle bounce and not a swear word.  A-X-L-E T-R-A-M-P.

[yossarian247]

10 hours ago, MikeEH said:

Anyone know why a word mentioned twice in my original post has been removed? It was a descriptive term for axle bounce and not a swear word.  A-X-L-E T-R-A-M-P.

A rather over-zealous (American) swear filter reacting to the t word I think. 

[Gerg]

As well as all the sound suggestions above, could your electrical and mechanical symptoms be related to VSC/anti-wheelspin operation of the brake calipers etc?  

Obviously the VSC system is not supposed to make that much noise when it operates, and if the electrical system is in good condition then it shouldn't hiccup when the extra load is turned on!

Also, although I've not had this happen myself, is there not a greater chance of diesel residue causing VSC operation on the exit from a service station?  

 

 

[TxXx]

Check brake calliper bolts, even when a bit loose they will float on the discs, but may produce the noise you are describing, and when you had the brief stall, may have locked one of the front wheels.

[MikeEH]

Well, got the car back from my friend's garage. He checked everything suggested on this post and everything else he and his son could think of and they found......nothing. He called me over to take his son out in the car in the hope that I could replicate the problems I've encountered. The flippin car behaved faultlessly. Isn't it typical. So I just have to keep on driving and if the problem occurs again to call over his garage straight away.

Thanks again for all the suggestions.