Drive shaft!!!!!

D

Duncan

True Classic
Took my car in for it's annual roadworthy check in the UK (MOT test). As you would expect being a Fiat it flew though the test apart from two items which I would not have guessed at.

Normally it's a blown bulb or brakes or emmisions or tires that it is likely to fail on. Bulbs I'd check, brakes I'd checked. Emmissions I hope for the best!

The failures were...

One was a missing manifold bolt (oops but fair enough!), the other was driveshaft bolts which apparently were loose. I would not have guessed it would fail on this in a million years. I think I never used a torque wrench when tightening the bolts!

Now going to have to pay for my slackness...
 
Well, at least those MOT test will keep you safe. I am not aware of any annual tests here in the states that would go to that level of safety spec (other than a race track).

Are there any penalties for failing (other than not getting the car registered I guess)? Can you have it done again right away?
 
Duncan said:
the other was driveshaft bolts which apparently were loose. I would not have guessed it would fail on this in a million years.
Click to expand...

Are you talking about the socket-head bolts that hold the CV joints together on a five-speed? If so, replace them, don't just torque up the old ones. These bolts see a serious fluctuating load, and if they've been allowed to loosen while under that load, the metal fatigue demon will have been nibbling on them... and it is really kinda no fun getting one out after it snaps off when you're trying to torque it up to spec.
(I have reused these bolts in the past, but only when I know the past history. Here you know the past history - and it says "not these").

I think I never used a torque wrench when tightening the bolts
Click to expand...
Not many places outside of the motor and transmission where the torque really matters... but this is one.
 
!

I'm not saying this to be mean: I've had more stuff broken during the actual inspection process that discovered wrong.

In other words, the inspection itself caused more problems.

Stripped cross-threaded wheel lugs
Closed the hood on a tool (inside out dent)
Big scratch in hood from screwing around with wipers
Scratched hubcap (trying to put an impact wrench on a simulated mag wheel hub cap)
Lost wheel center (different vehicle)
Broken radiator (accidently started truck trying to turn key on and drove into workbench)

Then I moved to Kansas where I don't have to get an inspection. All my problems are SOLVED!
 
Back in the early 90s (I think) Michigan threatened vehicle inspections. They built inspection facilities all over. Then pulled the plug. You can see these little shops (look like oil change places) all over, weeds 20 feet tall. Bureaucracy at it's best. Michigan doesn't inspect anything ever (that I'm aware of). I like it that way. If something fails dramatically on your car, you pay then. NEVER hear of much of a threat to the public, certainly not worth the inspection/bureaucratic nightmare/expense other places face.....IMHO.
 
penalties

If you leave the car at the garage and they make the repair then no charge. If you take the car away and fix it and return it within 10 days - they can re-test the area that has failed and give you a partial fee or do it for nothing. Some garages will insist on a full mot.

Normally the good garages do a retest for free - some of the bad garages charge a cheap fee for the mot and then fail loads of things so that they get the repair work. I had one instance where my brake pipes failed at one garage for slight pitting and when I took it to another garage it went through.
 
Kind of reminds me of the UK practice of contractor booting of cars...
It seems the Brits find rather creative ways of generating income be it non-government or by way of taxes..

Do, go to your local trade/industry fastener supplier and obtain 24 each of M8 (1.25mm thread) by 45mm long, socket head cap screws. They must be Grade 12.9.

Get a good quality 6mm hex bit driver to install these bolts on all the CV joints.

Replace ALL of them. These have a history of coming loose and leaving you stranded. In race cars, this problem can be serious. In the case of race cars, I fix this by boring out the threaded flanges and using MS21250 bolts, nuts and matching washers.. they do not come loose when this is done. And, the hex drive heads in the bolts tend to get knackered during the removal/installation process.

As for torque, If the cap screw and mating internal threads are dry and clean, 32 ft/lb might be OK, but if there is CV grease or bolts have CV grease or other lubricant on them, 32 f/lb will be too high. This cold stretch the cap screw during installation resulting in a cap screw failure. The ideal solution is to put a serrated and cones lock washer sperifically designed for cap screw between the cap screw and flange. Then, apply moly anti-seize to the clean threads and lock washer and flange then torque the cap screw to about 22 ft/lb.

The lock washers look like this:
http://www.mcmaster.com/#washers/=aosk1d

They are specifically designed for socket head cap screws.


Bernice

Duncan said:
If you leave the car at the garage and they make the repair then no charge. If you take the car away and fix it and return it within 10 days - they can re-test the area that has failed and give you a partial fee or do it for nothing. Some garages will insist on a full mot.

Normally the good garages do a retest for free - some of the bad garages charge a cheap fee for the mot and then fail loads of things so that they get the repair work. I had one instance where my brake pipes failed at one garage for slight pitting and when I took it to another garage it went through.
Click to expand...
 
Lock washer

The McMaster Carr reference for the serrated and cones lock washer sperifically designed for cap screws:

http://www.mcmaster.com/#washers/=aosk1d

gives the generic washer page.

I would like to use these, but am not sure of the exact description. Does anyone have a further description to help me source them locally?

Paul Davock
 
Mc Master Carr altered their web page, yes this link does not direct properly to the exact part. The Mc Master Carr part# 93501A030
Black Finish Steel Serrated Belleville Washer 5/16"/M8 Screw Size, .52" OD, .03" ThickIn stock at $9.75 per Pack
Bernice

PaulD said:
The McMaster Carr reference for the serrated and cones lock washer sperifically designed for cap screws:

http://www.mcmaster.com/#washers/=aosk1d

gives the generic washer page.

I would like to use these, but am not sure of the exact description. Does anyone have a further description to help me source them locally?

Paul Davock
Click to expand...
 
You must log in or register to reply here.
Back
Top