Took my sons 2008 Focus TDCi to the car wash, its one of those ones where you turn off the engine and it pulls the car through, it was attended. Lined the wheels up but the front made an odd sound like it had fallen off of something like the moving bit or maybe it was just the sound the machine made, not that I had noticed it before and have used it many times, car went through ok but on the way home I noticed a thud thud thud sound from the rear when driving. 

Got home and one of the tyre pressures was a little low so pumped it up and that was that until later this evening when I had to go down the dual carriageway. The thud thud thud sound is there, its like the feeling you get when driving with a puncture, yet there is no puncture and tyre pressures are what they should be. 

What on earth could be causing that? There is some shake in the car as well, not excessive but certainly not there before hand, thud thud sound is coming from the rear. Anything I should be looking at?

Thanks

Lift the car up at the back and place a chock or brick behind the other wheel and release the hand brake and spin the wheel and check for any issues/sounds. Also grab it 12 and 6 o'clock and shake it also 9 and 3 o'clock or get somebody else to do it and study behind. 

Check the inside tyre walls, look for buldge/egg. I once had the inside tyre wall badly damaged by a car wash, lucky for me I spotted  the "egg" sized bump on the inside just because of the way I had parked the car.

Thanks will take a good look at the wheels tomorrow 

Hmm, well more like an ostrich egg! Is this likely to be the culprit :-

 

I have noticed the car has those awful wheel nuts on with the caps that fall off, can anyone recommend replacement wheel nuts for my car? Had a look on ebay but wasn't sure exactly what I needed

That'll be a new tyre then. I'd also check the wheel rim isn't distorted too, as that looks quite bad. 

Tyres already ordered

Rim is fine, its the angle its taken at

How does a car wash cause this or is just a coincidence? 

Have no idea, but I know the car was fine before it went in and was vibrating/shaking when I drove home from the car wash. Its one of these car washes(I appreciate the picture is not from the UK but you get the idea) :

It was the wheel that was in the bit that pulls the tyre along. Whether related to the car wash or coincidence who knows

3 hours ago, jonj1611 said:

Hmm, well more like an ostrich egg! Is this likely to be the culprit :-

 

All that wasted tread.  

Tell me about it, not even a year old and only done a few thousand miles.

4 hours ago, AlanC2 said:

How does a car wash cause this or is just a coincidence? 

If your car is a bit too much off line as it gets pulled on to the conveyor it jams the sidewall of the tyre against the guide rail applies a side ways force on the tyre as it drags the car diagonally on to the conveyor.

I've had it happen to my car and I know of at least one other who has had the same. Thats why I guessed what was wrong when I read Jonj1611's orginal post.

I once had the boot trim of a Rover 75 almost ripped off in an automatic car wash. It ended up vertical held by a single fixing. That was the type of car wash where you just drove in and parked up with the handbrake on rather than the ones under discussion here. I'd positioned the car correctly, it was just the force of the horizontal brush as it went down the back of the car. That was in 2007 and I haven't used an automatic car wash since.

I did get a goodwill payment from the filling station and managed to get a replacement trim from a breakers, the original style being no longer available.

Until Covid hit I was getting our cars washed by a group of eastern europeans at my local Tesco. They did a good job using pressure washers spraying foam followed by a rinse and leather off.

You took a ROVER to a car wash !!!!!!!!!!!! I'm amazed there was anything left for you to sit in 🤣

2 new tyres on the rear and the car drives like a dream again

Ironically the car wash sent me a voucher for a Free car wash. Hmmmm