Help Me Diagnose Potential Car Issue

I am no expert - but brakes warped was my first thought.

However on second thoughts with it being an auto, is it something to do with the clutch or rear diff ?

Brakes on the trailer binding rather than those on the car?

Wheel bearing on the trailer? Check the temp on the wheels after use? Carefully!

<sharp intake of breath through teeth> your big ends gone...(apologies couldn't resist 😉 )

Had something similar when towing the caravan and in my case was the caravan brake that was the issue. Might be the trailer rather than car as suggested above

Wheel bearing?
Driveshaft/Propshaft imbalance (UJ gone or balance weight fallen off)
Gearbox issue (had something like this on a LR Discovery 2.7TDV6 - megaflush and autobox fluid replacement cured it)
Brake discs warped.
Trailer brakes issue with the trailer brake actuator

I'm going to hitch my own car up to trailer this evening and see if same thing happening. If not, then at least we know it's Mrs B car specific.

Trailer was new in December and no issues apparent until last night.

Looking at the rear discs on Mrs B's car, they don't appear to be so well 'polished' as my own, hence I'm thinking it may be a sticky rear caliper.

But...keep those ideas coming in. Thanks.

Horse scared and farting during braking and acceleration. Too much beans in the diet I diagnose.

Note I'm not a vet or a mechanic 😉

Trailer brakes are notoriously shit!

We've had a new towing hitch and brake overhaul on our Ifor Williams horse box. If they haven't been serviced in a while I'd start there. They just bind on as horse boxes are sat unused for long periods.

Especially if the noise isn't there when not towing.

Horse staggering around when car is jerking to a stop/start?

Or tap dancing

Trailer was new in December and no issues apparent until last night.

How often is it used? Drum brakes could be bound on if sat over winter?

Also - how many horses in and how steep was the hill? IIRC correctly X1s are on the limit for towing purposes, you might tow one horse OK, but two would be pushing it.

Good shout on change of tow car
Try the X1 in manual 1st gear only, if it'll drive safely, on the same downhill
Is yours FWD bias or RWD when X-drive not in play?

OK, bit of context and an update...

Trailer and car no issues at all after being used 5 days last week. Trailer taken home, cleaned and washed out on Saturday.

Trailer parked up on Saturday with brakes off (wheel-chocks used rather than handbrake on due to relatively infrequent usage..to avoid drum binding as above).

Trailer hitched up last night with horse in, first downhill braking bit and noise apparent...just at point of slowing down to stop and then when initially setting off. Turned back, unloaded horse and tested trailer unloaded. Issue still there in same scenarios. Unhitched trailer, drove car and no noise.

See how I get on with my own car pulling trailer tonight...

Mrs B has a 2010 X1 (E84) xdrive with the perm 4wd, I have a newer model X1 F48 also 2.0 diesel auto xdrive which I believe is FWD until 4WD required.

Trailer over run brakes
Notoriously shit, hard to set up and keep in balance.
If the juddering wss akin to being on a train with little shoves repeatedly then most likely this.
Beyond that, with deceleration and acceleration could be your misses is not even an average driver and is causing t, or any one of anout a dozen othet culprits
Diffs, propshaft, propshaft bearings, auto box torque converter, wheel or tyre issue, wheel bearings etc

OK, given issue not apparently when Mrs B's car is not pulling the trailer, have to assume it is some form of load related issue.

Juddering just at point of stopping when slowing down using brakes and just the initial pull away after having stopped. Noise and slight judder definitely sounds like it is coming from the back end and possible rear passenger side.

Interestingly, both rear discs on her car look much less polished than my own, even given hers pulls the trailer...does make me think some form of brake related issue, but also thought about propshaft, diff, etc, etc.

Could itbe abs or stability control system getting confused by the trailer and using the car brakes to control non existent stability issues?

How much nose weight is there on the trailer? If there's compensation valve that puts more braking effort on the back wheels when they have weight on them, that could be confusing the car. There are so many factors once you consider ABS and stability systems. Whether it happens on a different tow car will be useful.

Perhaps you just need to up your horse spend!...

[img] [/img]

🙂

There is definitely something which has occurred between Saturday and yesterday as the car and trailer combo have been absolutely fine until yesterday.

See how I get on with my car this evening.

Please don't go there....already doing horsey stuff on a small-scale feels akin to burning £50 notes...

I just keep quiet and nod now!! 🤣

It's the one thing I refuse to get involved with (I used to ride in my teens).

The wife rides, daughter rides (and now works for ex Olympic event rider), Sis-in-law rides, her two daughters ride - at last count there's about 12 horses between them... 😱

My Sis in law did take her HGV test last year though as HGV lorries can be cheaper to buy than non-HGV ones as fewer people have HGV licences.

And every bugger is an expert in the horse world! 🙂

The trailer brakes would come on as you go downhill and the trailer moves forwards on the hitch. As you pull away the brakes would still be on until its at full extension - always assuming your trailer has brakes that it but as its a horse box I'd assume it would.