MOT Time (Delayed)... and Mystery Bolt

steamship · #1 24th May 2022, 10:21 AM

Pleased to say that the car has passed yet another MOT with zero advisories.

It was due the MOT at the start of April but due to the continuing backlog here caused initially by faulty lifts (http://forum.a8parts.co.uk/showthread.php?t=15474) and then the virus, despite booking over a month early, the closest date I could get was the third week in May at a centre 65 miles away. Of the 15 centres we have, there was only one that had a slightly earlier date, and that was 90 miles away.

Anyway, job done. Now, a little test, brought about by doing some prep work for the MOT. Can you identify the mystery bolt? The only information you get is that it is approximately 68mm long. Bonus points if you can guess how much I spent on tools getting it out? MJ is excluded as she knows all about it, since I pestered her with questions.

tc4332 · #2 24th May 2022, 10:40 AM

I recognise the extractor bit.
End of my expertise.

HPsauce · #3 24th May 2022, 10:47 AM

I've no idea what it holds but I'll guess £3.50 on tools.

The conical seat suggests it's for something that solid and needs to be really secure but from the unthreaded length also quite deep, like brakes, but it's clean.
Or seats, but I think they're shorter?

MikkiJayne · #4 24th May 2022, 11:04 AM

Quote:

Originally Posted by steamship

MJ is excluded

boooo!

steamship · #5 24th May 2022, 12:21 PM

Quote:

Originally Posted by MikkiJayne

boooo!

Had to! Even if I hadn't pestered you, you'd know what it was for.

tonupkid · #6 24th May 2022, 07:51 PM

I'd guess
99p for the tool (postage excluded)
And that screw holds something like the screen wash reservoir

steamship · #7 26th May 2022, 02:54 PM

The offending article is item #33 in the attached image. It is the bolt that holds in the flanged shaft that the propshaft attaches to. This needs removing so that the infamous rear output shaft seal can be replaced (#31). The bolt in question is supposed to be torqued to a measly 25Nm.

I snapped a brand new T40 torx and wasn't even applying that much pressure. The snapped off section was stuck in the head of the torx and refused to come out, despite using little picks and various other items to try and shift it. Tried magnets, Araldite (overnight) and even something called Chemical Metal (overnight) to try and get a square head screwdriver to stick to it, but all were useless.

MJ suggested tungsten carbide burrs to drill the broken bit out which worked. Then had to hammer in a larger bit and then had a young lad with more strength and a breaker bar try to get the bolt out, but all we could manage was to strip the bolt more. Had decided to give up at that point and just live with the issue, and on my way to get some CV joint grease, thought about using a screw/bolt extractor (in the original photo), and on the way home considered freezing the bolt, despite the numerous times I'd read online about heating them. A quick trip to Screwfix and got some Arctic Products Crack-it. Followed the instructions on the can and after about 15 minutes the bolt broke free. Initially thought that the head had just snapped off with the pressure applied, but thankfully it was okay. As can be seen in the original photo, there was no signs of thread lock being used or it being cross threaded, so can only put it down to the enthusiastic 'mechanic' (and I use that term in it's loosest sense) who replaced it for me about six years ago.

Excluding the cost of the CV joint grease and the seal which I had to buy anyway, it cost about £41 in parts (Chemical Metal - £12, Burr set - £14, Screw/Bolt extractor set - £6 and Crack-it - £9), and all that for an issue with a £4 bolt.

Adrian E · #8 26th May 2022, 03:49 PM

Had a similar issue with a caliper bolt - luckily there’s a nice chunky head to it so was relatively easy to use a tungsten carbide drill bit and some lube to drill the head off and lift the caliper out of the way. At which point it just unscrewed…..

scottmgibb · #9 26th May 2022, 10:15 PM

Ohhh… I am just about to tackle this one, so hopefully my bolt has not been done up quite so tightly! It is actually the other side that is pouring out oil, but the right side is looking pretty damp too, so I will be changing both while I have the subframe and suspension all out and the access is a bit easier.

steamship · #10 27th May 2022, 09:11 AM

Quote:

Originally Posted by scottmgibb

It is actually the other side that is pouring out oil, but the right side is looking pretty damp too, so I will be changing both while I have the subframe and suspension all out and the access is a bit easier.

I saw your thread about the work you're doing, although I think you've mistaken which one I mean. Mine's was to the output shaft to the rear axle, not the front driveshafts, but I think they may use the same bolt. If they've never been touched since leaving the factory I think your's will be a doddle.

My front ones are okay which is good, because I don't fancy trying to do them in situ on axle stands.