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Edward · Alfa 33 Joined: 21 Sep 2003 Posts: 307 Location: Bristol

Hi,

Has anyone had problems with front hubs. I often seem to strip the threads out of the hubs - is seems that the thread is quite fine and reasonably easy to pull out with the bolt. I know you can put bolts with nuts through the outer holes of the hubs - but it is not possible on the inner as the casting is too close to the hole.

Also has anyone used studs for the wheels as opposed to bolts. What is it like trying to get these in. I am particularly looking for the mushroom ones that fit from the back - as these I imagine are a lot stronger. It looks like one would need to take the hubs appart to get the studs in from behind.

The hubs are to go onto my track car - which takes a lot of load. Much more that a normal road car - and I am trying to make sure that the whole hub assembly stays together.

Any suggestions would be muuuuuuuch appreciated.
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The faster the better.

RFlower · Posted: Tue Mar 07, 2006 12:18 pm Post subject:

Is it easy to strip these threads? Those on my Sprint had been professionally b*gg*r*d when I bought the car in Spain (the car had "FSH"). I repaired the threads with heli-coils, and had no problem reassembling without stripping again.

I think the problem is that the suspension spring wants to push the hub further down than the linkage wants to go.

As I recall, I either disconnected the lower swivel to allow the hub to more easily aligned, or used jacks to lift the parts into alignment before screwing the cleaned and lubricated bolts in by hand before finally tightening.
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Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

Ken McCarthy · Posted: Tue Mar 07, 2006 11:39 pm Post subject: Problems with hubs

Yes, I have also had some problem with these. It is a matter of getting the hub carrier and strut lined up. If you have an anti-roll bar, this needs to be disconnected or a simpler method is to jack both sides of the front so the other side drops to the same position. You have to get the holes lined up without any load on the joint and then get the bolts started by hand.

All the best
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Ken McCarthy - 16V Sprint

RFlower · Posted: Wed Mar 08, 2006 12:07 am Post subject:

Yup
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Dick Flower, Nr. Carcassonne. '94 Trofeo 1.4 ie (F), '93 Imola 1.3/1.4 ie (now for breaking) (F), '91 1.7 ie (GB)(spare car), '86 Sprint 1.5 QV (F). '87 VW Syncro camper (F), '73 NSU Ro80 (F), '99 Fiat Seicento (F)

Edward · Alfa 33 Joined: 21 Sep 2003 Posts: 307 Location: Bristol

Thanks Dick and Ken,

I don't so much have problems with lining things up - it is more that the thread in the hub seems so fine and vulnerable. I take your point about cleaning out the threads and lubricating and fitting by hand - but what I find annoying is that the thread seems so fine and inappropriate in the first place.

One thing I would like to understand is how the helcoils work - I have held a couple in my hand but don't understand how they work - could you explain.

Secondly, I feel it would be good to add studs from the opposite direction - between the hub and strut - the only problem is that I dont think you can get the stud in to the inner most holes as there isn't room due to the casting shape - has anyone found a way round this?
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The faster the better.

Vecchio Alfisti · Posted: Thu Mar 09, 2006 7:38 am Post subject:

The Helicoil screw thread insert is a well established engineering technique/practice used to reinforce screw threads in soft or weak materials such as Aluminim Alloys and to repair stripped or damaged threads in steel and other metals. The coil is shaped wire drawn to the form of a screw thread and wound like a spring. A special oversize tap is used to cut a female thread , the helicoil is screwed in and the the resulting female thread is available as a high strength wear resisting thread of the correct size. Because the wire is heat treated the helicoil is more wear resistant and stronger than the original thread in the original material. Because of the way the helicoil is drawn the thread profile is generally more accurate than a normally tapped screw thread would be. Loads are more evenly distributed on the parent metal.
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Alfa 33 1.7 QF I think maybe now I m not so sure

Edward · Alfa 33 Joined: 21 Sep 2003 Posts: 307 Location: Bristol

Wow,

Can't be much clearer than that as a description. Thanks for the clear explanation.
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The faster the better.