Axle Strap Horror

Tim Jobson · October 30, 2009, 12:30:52 AM

Well I had heard that removing axle straps as a swine of a job, I now can vouch for it,.

After trying everything, the bolts holding the straps were not budging so I then drilled out the axle straps so that I could then expose some of the bolts to get a pair of vice grips onto them. Because of the rusted state of the bolts they all snapped off about an inch from the body. One was just loose enough to unscrew the remaining the bolt the other three were frozen solid. I then chopped these bolts off close to the body work and then drilled carefully a hole so that I could then re tap the holes. After a weekends work I managed to salvage all the original bolt holes and their original threads. Probably the hardest job I have had to tackle yet on my 105!!!

I can see why these bolts are so difficult to remove because the canvas straps hold the moisture and provide a great moist environment for the bolts to rust in. In addition, the bolts have a hat type cover they scew into with a hole in the top of them. This hole allows water from the wheel well to sit on top of the bolts and thereby creating another lovely rusting environment. Not alfas best design feature. I will fill this category up with lots of anti seize paste.

My next task will be to fit new bushes in the rear trailing arms and also fit a brake pressure reducing valve that I got from alfaholics, I will need to practice my double flaring technique before I attempt this.

Cheers
Tim

MD · October 30, 2009, 07:55:28 AM

Tim,
Congrats on sorting out your problem.I was thinking about what you said and offer this suggestion. The anti-seize paste is definitely a good move and will save the captive threads. For future reference, to save the bolts from corroding as well, you could use 316 stainless steel ones (and washers).That would really nail the sucker.

1750GTV · October 30, 2009, 09:05:57 AM

Quote from: Tim Jobson on October 30, 2009, 12:30:52 AMMy next task will be to fit new bushes in the rear trailing arms and also fit a brake pressure reducing valve that I got from alfaholics, I will need to practice my double flaring technique before I attempt this.

Cheers
Tim

Tim,
If you want to keep the original pressure reducing valve, they can be rebuilt.
Chris

Barry Edmunds · October 30, 2009, 09:53:06 AM

Tim
I have been through this very same exercise so I can relate to your problems in removing the bolts. Also agree that this is one of the hardest jobs on any 105 series cars. Be careful using stainless steel replacement bolts. Stainless steel bolts won't rust but they may not be strong enough for the purpose. Strongly recommend that you use an anti-seize paste or copper grease on the bolts. Try and get some countersunk cap screw type bolts rather than the phillips head type originals. The capscrew bolts are much easier to remove as you can get a much better swing on them with an allen key tool than you usually can with a phillips screwdriver.
Barry

Tim Jobson · October 30, 2009, 04:33:47 PM

Yes I am going to use a high tensile 8.8 bolt and use lots of anti seize paste as I feel that stainless may not be strong enough. I will use a normal hex head bolt as I cannot see it really necessary to use a counter sunk head bolt just to secure the straps and rebound rubber.

I decided on a pressure reducing valve from alfaholics as I did not want to pay the same price for some hydraulic shop to remachine the old one and fit new seals to find out later that it either leaks or does not work. It looks like adjusting this new pressure reducing valve will be alot easier than the origional as another reason for going this way. Just hope I can flare new joints to make it all work!

This weekend will be cleaning the rear trailing arms and sway bar and POR15 it all.

Tim

MD · October 30, 2009, 07:07:58 PM

I guess the unknown is the tensile strength of the fabric straps ?
An A2-70 stainless bolt has a tensile strength of 700N/mm2. This would be of 304 grade.

cjheath · October 30, 2009, 09:57:54 PM

Quote from: MD on October 30, 2009, 07:07:58 PM
I guess the unknown is the tensile strength of the fabric straps ?

Actually, the force exerted on the bolts will be much less than the strength of the straps, if they're in good condition. Sorry to go all engineering on you, but the actual force depends on the maximum rate of extension of the axle away from the body (which is driven by the spring and limited by your damper settings), by the Young's modulus of the strap as it decelerates the axle, and of course by the effective mass of the axle being decelerated. Whether the bolts break over time depends mainly on whether they fatigue, which is more likely with stainless... but basically there are enough variables that there's no simple answer to whether the bolts will break.

When I bought replacement strapping material, I got it at Powerdrive Industries in Lexton Rd Box Hill... that was in 1987. I'm about to go back there and do this job again, since one of my straps got broken in the prang that almost killed my '69 1750 coupe (with TwinSpark) last year. I hope my bolts come out! It's been 22 years...

Tim Jobson · December 02, 2009, 10:47:12 PM

Well the worst job (so far) is now over, I have fitted new axle straps. The clamps that hold the straps together have been POR15 and SS bolts used. The aluminum block and metal plate was also POR15, new High Tensile bolts were fitted and plenty of anti seize paste that will keep it in good condition for another 34 years.

I am still thinking of a way to put a cap or some how plug the top of the mounting bolt housing to make sure no water gets to work down into the cavity above the bolts when water is sprayed around the wheel well!

Tim

MD · December 03, 2009, 07:41:02 AM

A shot in the dark here but would some polyurethane sealant be approriate? Unlike silicons, you can paint over this stuff.

1750GTV · December 03, 2009, 10:30:52 PM

Quote from: Tim Jobson on December 02, 2009, 10:47:12 PMwater is sprayed around the wheel well!

Water, water you say .....

This means you'll be taking your beautiful car out in the rain ? Surely not !

Washing should be OK as there is no mud involved - but wet weather, road dirt & grit - what are you thinking ?? Wet weather is for lesser vehicles - Holdens, Fords, Toyotas etc.

At some stage, I've also got to do my rear suspension. I'm not looking forward to it.

Chris

Tim Jobson · December 04, 2009, 03:37:23 PM

Yes Chris, my 105 will not be driven in the rain unless I am caught out. I any case I would like to find a way to seal the top mounting bracket to be sure.

Yes MD some way to seal it up without creating a different sort of rust trap would be good, I will need to put my thinking cap on!

I may even end up using my spray fish oil to spray the top of this mount on a regular basis along with the regular fish oil spraying of the inside sill areas that is now apart of my preventative maintenance routine.

Tim