I think i'm in trouble this time, there are four studs coming from the chassis through the leaf spring block and secure the Leaf spring on the car. One of those has damaged threads and i can't tight the nut. Anyone know how i can replace this long stud, there is no access there

I did have one of these studs sheer off when removing a leaf spring once. The heads of the studs are in a triangular (toblerone) box section which is below the floor where your feed go onto the pedals. I fixed it by drilling out the old stud from below, and then keep going to drill through the floor panel above. Then inside the car I enlarged the hole in the floor until it was big enough to take a Bolt head and a socket on a short extension bar. You then need an assistant to hold the socket spanner inside the car while you fit the nut from below.

Can you not re-tap the thread?

Replacing these studs is very difficult as they are in an enclosed 'box' section. 1 option is as 'Duffy's dad' suggested; another option is to run a thread 'tap' up the damaged section of thread, tighten the nut up as much as you can, and then use a 2nd nut to lock the 1st nut in place--there is normally enough thread on the stud to allow you to do this (I have had to use this dodge). If the isn't enough thread on the stud to allow you to do this, use a spacer (normal nut with the thread inside it drilled out) instead of the 1st nut. :bang:

the hobbler said:

Replacing these studs is very difficult as they are in an enclosed 'box' section. 1 option is as 'Duffy's dad' suggested; another option is to run a thread 'tap' up the damaged section of thread, tighten the nut up as much as you can, and then use a 2nd nut to lock the 1st nut in place--there is normally enough thread on the stud to allow you to do this (I have had to use this dodge). If the isn't enough thread on the stud to allow you to do this, use a spacer (normal nut with the thread inside it drilled out) instead of the 1st nut. :bang:

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Yes this is what I am planning to do, the stud can easily take two nuts or a few washers and a nut.I will try to find the torque since I don't want to damage the remaining thread. I think it will work.

Thomas

The other alternative is to cut the stud off with about 10mm left sticking out.
Then cut the head off a new bolt. Taper the end of both pieces and then weld them together and ground the weld down smooth

I will go for the easier way first, I'm just not sure if i can fit standard M10 nuts with 17mm spanner size because original ones are M10 14mm spanner. I will give it a try later today.

I got bad news and good news. Bad news is that all the exposed thread is damaged all the way, i put two nuts but i am not comfortable with it.:bang: The second stud is also damaged since i can't remove the nut:bang: It turns quiet stiff but wont come out so i got to cut it with my dremel tool.
Good news is that someone been there done that before and there is a 2in hole opened on the floor just in the middle of those two studs so i hope both will come out easy since they are welded but with just one spot.

I think that what you have discovered explains the cause of your problem. If the studs aren't positioned exactly right, you will damage the thread when fitting/removing the spring mount. I would suggest that when you come to spot weld the new studs in place, you do it with a spring mount bolted in place and WITH THE SPRING FITTED. Carefully measure the alignment of the spring to ensure that the spring is correctly aligned vis-a-vie the body of the car prior to welding the heads of the new bolts. Have a new set of the mounting rubbers to hand (the 'cushion' that goes between the spring and the aluminium mount) as there is affair chance that the heat of the welding will carry down the stud and damage the rubber---have fire extinguishing equipment easily to hand!! To assist with the correct alignment of the stud I would be tempted to have some sort of spacer over the stud (a piece of thick-wall tubing, or even just a pile of washers) so that the stud is aligned in such a position that removing/refitting the spring mount doesn't damage the thread on the stud. I would suggest that when the studs were replaced earlier in the car's life, these location precautions were NOT carried out--hence the slight misalignment of the studs, which cause the thread to be taken off.
Whenever I have fitted these aluminium mounts I have liberally coated the part that contacts the car's underbody with "copperslip"--it really does help if you ever have to take the mounts off at some time. I would also recommend that you liberally coat the stud where it goes through the aluminium mount with "copperslip" as well---aluminium and steel love reacting against each other and causing seizure!:bang:

Hi Thomas,

Using a Dremel can be quite slow. :bang:

In a workshop I'd probably use an Oxy-Acetylene torch to heat up the nut,:devil: sometimes this enables removal. It's possible that the nut has stripped the thread that's underneath the nut, so it's very difficult to get the nut to engage with the thread below it, it just goes round and round.

At home, I'd probably drill 2 holes vertically into the nut, one each side of the stud, then split the nut with a chisel/

Nut-Splitters can be great but unfortunately often you can't get them into the required position, as is likely the case here.

Tom's (the hobbler) solution sounds very workable. .

Another possibility is to enlarge the hole in the floor, weld 2 bolts to a piece of flat steel (with 2 holes drilled in it) and then drop this into the hole and tack weld this to the box section. (gives you more room to weld and something of a lighter gauge to weld to the relatively thin metal of the box section). As regards alignment (very important!), it might be possible to measure from the other mounting (assuming it hasn't also been 'worked on') to a central datum point and use this measurement to align the mounting you're repairing. I reckon you could also measure from each spring eye in turn to a rear suspension mounting or hub centre to assist alignment (i.e. to keep the wheelbase the same on each side).

No doubt, you'll also check that there's no cracking or other damage around this spring mounting point due to previous accident/ collision/ corrosion/ or possibly running loose for a while.

Good luck with the repair

AL.

Tom and Al since I can't weld it right now I will just put two bolts and use a seccond person to help me tight the nuts (I hope my 9 year old son will help me), i don't see the reason to weld them again anyway. I will pay atenaion on alignment ofcourse.
Between aluminium mount and chassis i will put a special stuff we are using on aircraft similar applications called CA 1000 (check ppg aerospace for specs). It will last forever and cannot be penetrated from water. I just hope that the mounts will come off easy and they are not one with the bolts and chassis.
Thomas

F123C said:

At home, I'd probably drill 2 holes vertically into the nut, one each side of the stud, then split the nut with a chisel

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As you advised Al, i drilled 3 holes vertically at 6 and 12 o'clock on the nut and then split it with my chisel. Bolts came out with the hummer. I was lucky enough and removed also the other side aluminium block without damaging the bolts, it was hard to remove but it came in the end. Now i have to paint the beam and put everything back

Well done Tom! A little dodge that I learnt many years ago. Look at the aluminium mount on the left of the photo (the mount that is upside down). File a small slope on the edge of the base, level with the 'cross' on the underside. Make this slope wide enough that should you ever have to take the mounts off again, you can tap an old wood chisel (wood chisel because they normally have a much finer angle on the blade) into that slope--it will make it easier to start the mount moving. If you don't do this, it can be very difficult to get a seized mount moving down the studs. Liberally smear the studs and the underside of the mount with 'CA 1000' to help prevent steel-to-aluminium oxidisation (and seizure). I apologise to any carpenters in the forum for using a wood chisel in this manner, but I did say 'an OLD wood chisel'.

Good idea Tom, I was looking for such a slope to put my chiesel with no luck so yes I'll file one at each side for next time.
As i said i was lucky enough with this one with the help of my BIG hummer ofcourse.
Thomas

2 other thoughts occurred to me :-

1) Nowadays many garages use 'induction heating' equipment to free-off frozen nuts. e.g. wheel or suspension nuts. These come in kits that have different size heating coils that fit around the fastener head - this gets the heat to exactly where it's needed without any risk to adjacent components.

2. Nowadays, instead of welding, some body panels and other metal parts are bonded in place using special industrial 'adhesives'. Might be a very easy way of holding a captive bolt in place/prevent it from turning instead of welding.

If you don't have welding equipment, you could always drill 2 holes, suitably spaced, in a piece of flat steel, bring it to a welder and ask for 2 suitable bolts to be tack-welded in place. This 'assembly' can then be fitted to the box section through the access hole you've cut. If this access hole is in a structural member, it might be advisable to weld/bond a cover plate in position afterwards.

AL.

I'm just about to replace my front leafsprings next week.... as I found one of the leafs snapped!!! I REALLY hope I will not need the info in this thread

A little piece of advice, support the leaf spring with your jack, then remove the nuts and then lower your jack to take the spring out. The opposite on installation, just don't let the nuts take all the load and drive the leaf spring to its final position, let the car jack do that. Also the torque for the four nuts is 346 in/lb if you are using a torque wrench.
Good luck and let us know

Thomas

A piece of advice for before you fit your new spring--which I had to learn by tedious experience! Before you fit the new spring, carefully measure the distance ON BOTH SIDES of the spring between the ridge on the top leaf (that locates in the aluminium mounting block) and the centre of the eye that the bottom suspension upright goes through--the measurement should be the both on both sides. However, there is fair chance that there will be a discrepancy. Being that the central-bolt in the spring does nothing for the location of the spring (it just holds the various leaves together) it is important that the 'ridge to bush' measurement is the same each side.
If it isn't, it will need to be corrected, otherwise your suspension can take on a very lop-sided appearance. To rectify the fault is easy, just tedious. First of all ascertain the difference side-to-side. (the difference on my spring was 8mm!). Clearly mark which side of the spring goes to which side of the car, and KEEP TO THAT LOCATION. Clamp all but the top spring leafs together with good strong clamps (old-fashioned metal G-clamps are the best for this) where the 'wrapround' straps are and then remove top leaf by undoing the central bolt. Then elongate the bolt hole in the top leaf(with a round file) by HALF the distance difference on the SHORTEST side. Refit the top leaf, with the leaf moved over as far as possible towards what was the longest side. By doing this you will have shortened the distance between the ridge and the bush on what was the longest side by 1/2 of the original discrepancy and lengthened the distance between the ridge and the bush on what was the shortest side by 1/2 the original discrepancy. Re-check measurements--they should now be the same on both sides. As a safety measure, get your local garage/machine shop/blacksmith to back-fill the original bolt hole so that you are finally left with just the bolt hole that is required. clean up hole and spring-leaf with appropriate files. After fitment of the new spring check camber angles---on a standard 500 the measurement is 1deg +/- 20 minutes positive (i.e. the wheels lean OUT at the top). Adjustment of camber is made by adding/subtracting shims between the inner wings and what Fiat call 'the swing-arm pin'---the yoke that the top wish-bones pivot on.