Technical Thread stripped on front wheel hub flanges

[AAB1992]

Hello there,

I've got a 68 plate pop with 42k on the clock. Yesterday I wanted to check the front brake pads and discs. When I came to remove the front wheels I found several wheel bolts difficult to remove. Bearing in mind the wheels had already been removed in January.

Anyway to cut a long story short one thread on each side has stripped (not badly) but enough to have me annoyed! I’ve never had this issue before on any car, even the previous generation panda that I’ve owned for 12 years now. I always use a torque wrench to tighten my wheel bolts to 85NM.

My thoughts are the metal that the hub flange is made from is like cheese. In addition, water and salt has got behind the hub assembly and almost corroded the bolts in place

I was thinking possibly to peruse Fiat for a warranty claim but I doubt I’ll get far. Having looked on Eper for the part numbers, the hub flange is different to the older panda/500 so you can only get them from a dealer at £150 quid each!!! So if the wheel bearings also need to be replaced at the same time the job could easily be £500+. A very poor outcome for such a new car.

I had a brain wave this morning why not helicoil the damaged threads? I’ve seen it’s possible to do, and I have used them before for various applications.
I’ve already got an M12x1.25 kit but having measured up the hub flange and how far the wheel bolts actually go in I’ll need 1D (12mm).
What are people’s thoughts doing on this?

I have to say this car hasn’t been totally trouble free throughout its life and this seems to me another example of cheaply manufactured parts. How would I stop this happening again in future?

Adam

 

[Herts Hillhopper]

has the car got non-OE locking wheel nuts, and was it those thread holes that have stripped? (Just wondered if they might not have been the right thread)

 

[AAB1992]

has the car got non-OE locking wheel nuts, and was it those thread holes that have stripped? (Just wondered if they might not have been the right thread)

They are the original wheel bolts. The car has steel wheels so no locking nuts. It’s very odd that it’s happened on such a new car. The bolt threat has damaged as well

 

[murphyv310]

This is very strange.
My previous 2014 lounge lived by the sea before I purchased it. The front discs were badly corroded but the wheel bolts and hubs were fine. Many say you shouldn't use copper grease on them as then they need a different torque setting. I disagree with this as I've used copper grease on wheel bolts or nuts in 50 years of driving.
I don't think the hubs are cheese on the Panda, I'd be looking for another explanation, were they crossed at some point in the past etc.

 

[portland_bill]

I think I'd be reluctant to use helicoils on wheel bolts, but that is just fear, not for technical reasons. A properly done helicoil is stronger than the original thread, which is why they are sometimes used in aluminium fixings from new. As it is only one each side, as long as the other three are fine, it is obviously cheaper than new hubs.

My guess is that the damage has been caused by idiot fitters using air guns to refit the wheels.

 

[AAB1992]

I’m the only person who’s ever done work on the vehicle so that can’t be the explanation. My personal feeling still is that there is something not right with the material on these hubs.

There’s no harm in trying helicoil, worst case scenario is I’ll have to just change the hubs

 

[portland_bill]

I’m the only person who’s ever done work on the vehicle

The car is less than 3 years old, so still under warranty.

Are you a dealer mechanic, or has it never been serviced by a dealer, since new, and never been to a tyre shop? Your statement just seems a bit unusual.

 

[AAB1992]

The car is less than 3 years old, so still under warranty.



Are you a dealer mechanic, or has it never been serviced by a dealer, since new, and never been to a tyre shop? Your statement just seems a bit unusual.

I’m self learnt, over 10 years of experience. I’ve planned to keep the car for a long time so I’ve done servicing myself. The local fiat dealer near me is utterly useless

 

[chris3234]

I’m self learnt, over 10 years of experience. I’ve planned to keep the car for a long time so I’ve done servicing myself. The local fiat dealer near me is utterly useless

We'll somthing must have gone wrong at some point as I don't think I've seen anybody on here who's had this issue before?

 

[AAB1992]

We'll somthing must have gone wrong at some point as I don't think I've seen anybody on here who's had this issue before?

That’s what I don’t understand I’m quiet competent I can change a clutch and I’ve done a top end rebuild. It very much feels like the winter salt and water has caused some sort of corrosion at the other end of the hub and stripped the thread when I tried to remove the wheel nuts. I have never come across this before myself personally even on my older 169 panda

 

[Pugglt Auld Jock]

Some thoughts running at random through the little grey cells.

1) How old is the torque wrench? I was most surprised to find my old Britool, which I'd had checked and calibrated before I left work quite some years ago, was setting fixings noticeably higher than the scale indicated. I had already bought an electronic one so I stripped the Britool and it's "clicker" was gummed up (much to my surprise). Torque wrenches need regular servicing just like all mechanical devices.

2) Is it a "good" make? A cheap torque wrench, in my opinion, is a poor investment.

3) Stop using that torque wrench until it's been checked and calibrated if necessary.

Personally I would use a helicoil in a hole where the fixing is going to be set in place and not then removed again (or at least not dismantled very often) - head bolts, water pump fixings, gearbox casing bolts, etc - I've had helicoils wind out again when used in situations where frequent dismantling is called for. If I were going to do a thread repair for something which is going to be periodically dismantled I'd be using a Time Sert: https://www.youtube.com/watch?v=anjDQJtWFc8

You'll notice the insert has a locating flange? If there is room to get at the back of the hub flange and the shape of the casting allows it, I would be tempted to install the insert from the rear so the wheel stud is pulling against this locating flange when tightened and I'd probably put a wee bit of loctite stud lock on the insert when installing it.

 

[KPat]

"When I came to remove the front wheels I found several wheel bolts difficult to remove."

I think the clue is in that statement. Either overtightened, cross threaded or rusted?

 

[Pugglt Auld Jock]

"When I came to remove the front wheels I found several wheel bolts difficult to remove."

I think the clue is in that statement. Either overtightened, cross threaded or rusted?

The same "dreaded" feeling as you remove those tight bell housing bolts and watch the wee whispy threadlike curls of metal coming out with them!

 

[KPat]

The same "dreaded" feeling as you remove those tight bell housing bolts and watch the wee whispy threadlike curls of metal coming out with them!

I have noticed on cars which use this type of wheel bolt that you can screw the bolt in by hand right up to the point of applying the wheel wrench for the final half turn or so. Same thing in reverse when removing.


They should not be difficult to remove.

 

[timmycm850]

Hi All

irrespective of the cause, reading all the previous posts I would probably look at converting to 8 studs and nuts, whilst fitting the studs into the hub I would heli-coil any that are suspect and threadlock them all in, this will stop any concerns over unwinding the heli-coils.

I hope this makes sense

Tim

 

[Pugglt Auld Jock]

Hi All

irrespective of the cause, reading all the previous posts I would probably look at converting to 8 studs and nuts, whilst fitting the studs into the hub I would heli-coil any that are suspect and threadlock them all in, this will stop any concerns over unwinding the heli-coils.

I hope this makes sense

Tim

Hmm? I see what you mean, Permanently install studs in the flange and then use taper fixing nuts like BMC did it with the Mini, Cambridge, etc, etc?. As long as you get nuts with the correct taper to mate with the taper on the wheel I quite like this idea. However, as it's completely "non standard" you might be wise to run it past your insurance provider - They just love to find a reason not to pay out if they can!

 

[AAB1992]

Just to pick up on a few points raised so far....

The torque wrench is about 5 years old and purchased from Halfords from when I used to work there. I believe they were Norbar wrenches at the time. So decent quality. Never use a torque wrench for undoing!

I’ll try a helicoil with some threadlock. I did some research this morning and Loctite 270 should do the job. I think an m12x1.25 1D may protrude a little as I measured the flange to about 10-11mm thick.

At the minute it’s all purely theoretical as it all depends if I can actually drill out the old thread, tap it and do that without the hub moving at the same time so I can get it square and not at an angle.

Most of the nuts were harder to remove than I’ve ever recalled in the past but most of the came out without fuss except the two in the picture. I was the last person to remove the wheels and tighten them back up. I also had the rear wheels removed at the same time in January, I tightened them up using the same wrench, with no stripped thread on the rear hub when I took the wheels off recently.

I always insert wheel bolts by hand it’s just a given and routine. I feel stupid for raising this issue on such a new car but I can’t understand what’s happening. Is it possible for corrosion to occur within the space of a few months? Do the wheel bolts travel all the way through the hub flange and protrude out the other side.

I really can’t justify Fiats stupid pricing at £150 per flange. I’d like to make a permanent and safe repair without going down the route of stripping everything down, with the associated time and Labour costs.

 

[Goudrons]

Those bolts look fubar at the thread ends.

If you can get the hub off, take it to a local motor engineers and get them to fit a proper thread insert.

A Helicoil might be ok, but if you don't get the drilling and thread straight, you'll end up with a wheel bolt at an angle and the bolts seat will not spread the load evenly, it'll just pinch up one side.

 

[chris3234]

View attachment 217929

Just to pick up on a few points raised so far....

The torque wrench is about 5 years old and purchased from Halfords from when I used to work there. I believe they were Norbar wrenches at the time. So decent quality. Never use a torque wrench for undoing!

I’ll try a helicoil with some threadlock. I did some research this morning and Loctite 270 should do the job. I think an m12x1.25 1D may protrude a little as I measured the flange to about 10-11mm thick.

At the minute it’s all purely theoretical as it all depends if I can actually drill out the old thread, tap it and do that without the hub moving at the same time so I can get it square and not at an angle.

Most of the nuts were harder to remove than I’ve ever recalled in the past but most of the came out without fuss except the two in the picture. I was the last person to remove the wheels and tighten them back up. I also had the rear wheels removed at the same time in January, I tightened them up using the same wrench, with no stripped thread on the rear hub when I took the wheels off recently.

I always insert wheel bolts by hand it’s just a given and routine. I feel stupid for raising this issue on such a new car but I can’t understand what’s happening. Is it possible for corrosion to occur within the space of a few months? Do the wheel bolts travel all the way through the hub flange and protrude out the other side.

I really can’t justify Fiats stupid pricing at £150 per flange. I’d like to make a permanent and safe repair without going down the route of stripping everything down, with the associated time and Labour costs.

Those bolt look extremely rusty for just 3 years old
I've got bolts on a 20 years old motorhome that are in better condition them those are

 

[AAB1992]

Those bolt look extremely rusty for just 3 years old

I've got bolts on a 20 years old motorhome that are in better condition them those are

The all looked fairly similar, I’ve not taken the back ones out to look. You can see on the thread rust from where they have been screwed in. I wonder if it’s a bad batch of bolts or something along those lines.

I was always under the impression wheel bolts must be inserted dry but I’m starting to wonder if some sort of anti corrosion film is needed on them? Or replace all the bolts with ones from another car.

I’ll have pics to follow once I take the discs off and calliper