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Caliper bolts holding up C-19 rebuild


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It was all going too well! Like many others I have been using my time 'off' on furlough to rebuild my 1993 90 onto a galv chassis. Until now it has been easier than I expected. I am now on the rebuild stage and tackling the brakes. I am replacing the entire rear system as the calipers are badly rusted. First caliper bolt dissolved as soon as I put a spanner on it - I didnt even get a change to put any sort of pressure on it before it rounded. I knocked a smaller size socket onto it and it got a good hold but would not budge, until it slipped and rounded the head. Bolts 2 and 3 were very tight but came out with a long bar (and extension). The last bolt snapped as soon as I put the socket on - I didnt even get the chance to put the long bar on it. 

So I now have 1 caliper off, the hub stripped down to access the bolt hole and a bolt snapped inside the hole. The second caliper cannot come off as the head is rounded. 

Help!! I have drilled out about a 6mm or so hole in the snapped bolt and tried stud extractors and a bit of heat (I didn't have the heat when I snapped them). It wont budge and I am scared the stud extractor breaks. I have not attempted anything on the rounded head yet.

Any suggestions or experiences to draw on??

Cheers

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Irwin bolt grips have got me out of similar issues in the past. Worth their weight in gold! 

A good hot weld of a nut on the end can also work wonders if you've got access to a welder.

21 hours ago, Bowie69 said:

Cut the head off with a grinder, remove caliper and attack with heat/stilsons.

With a caliper bolt wouldn't the disc stop you? :unsure: :( 

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25 minutes ago, landroversforever said:

Irwin botls grips have got me out of similar issues in the past. Worth their weight in gold! 

A good hot weld of a nut on the end can also work wonders if you've got access to a welder.

With a caliper bolt wouldn't the disc stop you? :unsure: :( 

I've used these heaps of times on calipers with great results, screw - tap on with hammer - tighten a little more - tap with hammer - make sure its properly seated then give it some grunt with a breaker, not failed to get any out up to now.

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7 minutes ago, Maverik said:

I've used these heaps of times on calipers with great results, screw - tap on with hammer - tighten a little more - tap with hammer - make sure its properly seated then give it some grunt with a breaker, not failed to get any out up to now.

Not to underestimate the tapping either... you need them to bite or they machine the bolt heads into a lovely taper.

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Sounds like I need to invest in some Irwin grips then. After wasting most of the day yesterday and a couple of hours this morning, I threw a tantrum and gave up on the rear axle. (I might sneak up on it when it is not expecting it and surprise the bolts into submission! 😛 :) ).

So started on the front axle - nice new swivel hubs for both sides. I couldn't remember the size of socket/spanner for swivel to axle bolts, so held up a 15mm against the first bolt and it crumbled to dust - nothing on the head to grip with spanner. (I didn't even try to slacken the nut just put the spanner up to it to check the size!). looking at the rest it looks like they are all going to do the same (both sides). :( 

So it doesn't look like there is room to get Irwin grips onto these bolt heads. Since the hubs are trash anyway I was thinking about cutting the heads off all the bolts to allow the swivel to come off and then get nuts welded onto what is left of each stud to wind them out?? - Any flaws to that plan??

 

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1 hour ago, Mean Green said:

Sounds like I need to invest in some Irwin grips then. After wasting most of the day yesterday and a couple of hours this morning, I threw a tantrum and gave up on the rear axle. (I might sneak up on it when it is not expecting it and surprise the bolts into submission! 😛 :) ).

So started on the front axle - nice new swivel hubs for both sides. I couldn't remember the size of socket/spanner for swivel to axle bolts, so held up a 15mm against the first bolt and it crumbled to dust - nothing on the head to grip with spanner. (I didn't even try to slacken the nut just put the spanner up to it to check the size!). looking at the rest it looks like they are all going to do the same (both sides). :( 

So it doesn't look like there is room to get Irwin grips onto these bolt heads. Since the hubs are trash anyway I was thinking about cutting the heads off all the bolts to allow the swivel to come off and then get nuts welded onto what is left of each stud to wind them out?? - Any flaws to that plan??

 

These are the bolt grips: Irwin 394001 Bolt Grip Fastener Remover Base Set of 5, Multi https://www.amazon.co.uk/dp/B00ID6E8OM/ref=cm_sw_r_cp_api_i_DoM4EbHJK99KW

IMO worth getting the expansion too. 
As for the swivels, usually once you’ve got the tension off it, they wind out pretty easily. So cut head(s) swivel off and then pliers or grips should be enough on what’s left. 

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So - as an update.... 2 x rear caliper bolts are still holding up the entire rebuild. So far I have spent almost £150 trying to remove bolts that cost 27p each!! 

As an aside - it looks like the front bolts are in a similar condition and are going to be just as much of a PITA!! 

I am waiting for a friend to come along with his welder and will weld some new nuts on to the broken/rounded bolts and hopefully they will get me back on track ASAP. 

I had hoped to have the rolling chassis mobile and stopping under its own steam during the lockdown furlough - but it looks like I will be back to work next week. 

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So another update.. mixed success. 

The rear caliper with the rounded head is now off - I drilled out an M12 nut to 13mm, knocked it over the rounded head and welded it on. After a few attempts and a few broken welds (novice welder) it came off. 

Both front calipers came off with a lot less hassle than I thought- combination of 1/2 and 12mm sockets knocked over the bolts and a good dose of plus gas and they came away. 

The problem is the snapped bolt - I have drilled out out as far as I dare - I am up to 10mm drill, I believe it is a 12 mm thread - and I was expecting it to give up a some point, but no it is hanging on in there. As I need to get this right first time can anyone confirm the exact spec of the thread for caliper bolts? I need to buy a tap to a. clean out the rest of the threads and b. re-tap the rear hole. if my reading is correct is it 'M12 fine' but what is the spec? google gives me M12 x 1, M12 x1.25, M12 x 1.5 - all claiming to be 'M12 fine' ??? 

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Under FTC3375, LRWorkshop show it as M12 x 1,25; 35 mm ; 20 mm thread; steel 10.9; double hex. (I would call the head 'bi-hex), but no matter).

LRW also state the current number is SYP500090 and while that gets results from more suppliers, I haven't found one that mentions the thread form.
You have managed to unscrew at least one, surely you can measure the pitch yourself (1.25mm)? If not, it's a good prompt to buy a thread pitch gauge.

I see that under SYP500090 they are available as sets on eBay, but appear to be much more expensive per bolt than buying from a LR Supplier.

Regards

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1 hour ago, Mean Green said:

Thanks for all the replies - it is a very late 1993 with disc brakes, so part number FTC3375. Which is M12x35x1.25 - so i need to source an M12 x1.25 tap.

Any good tool shop should be able to sell you one

 

Edited by mmgemini
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Success. Caliper bolt is out! Drilled out at 0.5mm increments until 10.5mm. I could then see threads so used the tap and cleared it out. All ready to rebuild the hub.... except one of the brake disk bolts snapped in the hub (typically the last one).

Front swivel hub to axle bolts on passenger side were no problem, all came away with no trouble. Drivers side was a different story - 6 out of 7 heads rounded. Decided best way to get to them was to cut the swivel ball off. I started off with a 9 inch grinder and cutting disk, but heat from a grinder and grease in the swivel did not mix well. Once the smoke cleared I finished it by hand with a hacksaw. Knocked a 13mm socket on the the heads and they came away fine, with the help of a 2 foot breaker bar.

So a little more progress.  

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