Niamh Posted October 2, 2015 Share Posted October 2, 2015 Got the front calipers off and replaced no problem. The rear right caliper came off with a bit of "naughty" effort wiht an 1/2" air wrench. But can I get the top bolt on the left rear caliper to undo? Can I buggery! Can't get a decent approch with the air wrench as there's the spring and the exhaust in the way. So any tips to get this bolt out? Niamh Quote Link to comment Share on other sites More sharing options...
Tanuki Posted October 2, 2015 Share Posted October 2, 2015 They're fitted using a blue thread-locking-compound at the factory. Heat the head until it's red-hot with a gas-axe. The heat will conduct down the bolt and soften the locking compound. Hit it *really hard* square-on with a drift and a lump-hammer to break the lock. Then heat it until it's red-hot again and then use a proper 12-point socket on it. Quote Link to comment Share on other sites More sharing options...
Nigelw Posted October 2, 2015 Share Posted October 2, 2015 If it gets bad cut the head off with a slitting disc on the grinder and drill it out, I remove the hub usually and drill it from the outside in, less metal and a lot more room often drilling it out to 6.5mm and walloping a 7mm coach bolt in works, failing that be sure you drill it central an square as big bits carve more meat! Dont want to mutilate a thread if you can help it. Quote Link to comment Share on other sites More sharing options...
Igol Posted October 2, 2015 Share Posted October 2, 2015 Irwin bolt grips and a wrecking bar with a lake of penitrating oil and blow lamp worked last time I struggled with the sods and was thinking I'd be doing the drilling out thing. Quote Link to comment Share on other sites More sharing options...
Niamh Posted October 3, 2015 Author Share Posted October 3, 2015 They're fitted using a blue thread-locking-compound at the factory. Heat the head until it's red-hot with a gas-axe. The heat will conduct down the bolt and soften the locking compound. Hit it *really hard* square-on with a drift and a lump-hammer to break the lock. Then heat it until it's red-hot again and then use a proper 12-point socket on it. "Gas-axe", I'm guessing you don't mean an ordinary propane blowtorch? Which I'm a bit reluctant to use given the broad spread of heat and the fact that there's a rubber oil seal not to far away on the hub. The rear spring is right in the way of doing anything "square on" Niamh Quote Link to comment Share on other sites More sharing options...
Niamh Posted October 3, 2015 Author Share Posted October 3, 2015 If it gets bad cut the head off with a slitting disc on the grinder and drill it out, The body of the caliper gets in the way of a neat square cut though I remove the hub usually and drill it from the outside in, less metal and a lot more room often drilling it out to 6.5mm and walloping a 7mm coach bolt in works, failing that be sure you drill it central an square as big bits carve more meat! Dont want to mutilate a thread if you can help it. And even when the head's cut off one cant remove the capiper because of the hub, which can't be removed until the caliper's off. Niamh Quote Link to comment Share on other sites More sharing options...
Niamh Posted October 3, 2015 Author Share Posted October 3, 2015 Irwin bolt grips I haven'y mullahed the head... yet! Niamh Quote Link to comment Share on other sites More sharing options...
GW8IZR Posted October 3, 2015 Share Posted October 3, 2015 I've had to resort to miging a bolt to the head which allows a better connection and the heat tends to loosen them anyway. Quote Link to comment Share on other sites More sharing options...
Niamh Posted October 3, 2015 Author Share Posted October 3, 2015 I've had to resort to miging a bolt to the head which allows a better connection and the heat tends to loosen them anyway. That's scary territory! Last time I did any welding on a Disco I wrote it off- The centre console by the handbrake caught fire, I was welding the nearside front wheel arch at the time! Niamh Quote Link to comment Share on other sites More sharing options...
GW8IZR Posted October 3, 2015 Share Posted October 3, 2015 That's scary territory! Last time I did any welding on a Disco I wrote it off- The centre console by the handbrake caught fire, I was welding the nearside front wheel arch at the time! Niamh Well if you're not confident with any of the techniques it's easy don't do it. You shouldn't have any trouble though, good earth clamp connection close to what your welding, clean what your welding, think about where the current will flow ( don't clip to the body and weld on the axle ) it's sensible to remove the battery earth, think about the fuel tank and lines etc... The calliper will get a bit hot if you aren't careful so think about the rubber components... But as I said, not confident, don't do it. Quote Link to comment Share on other sites More sharing options...
Niamh Posted October 3, 2015 Author Share Posted October 3, 2015 The calliper will get a bit hot if you aren't careful so think about the rubber components... That's being binned anyway. Niamh Quote Link to comment Share on other sites More sharing options...
Les Henson Posted October 3, 2015 Share Posted October 3, 2015 Been a while since I did one, but if I remember right I disconnected the shock absorber and with the increased drop I was able to get straight onto the bolt head with an extension through the spring coil. You can also put a bar on the bolt head and give a good few hard whacks with a hammer. This sometimes helps to undo stubborn bolts. Be careful not to deform the head though as the socket may not go on. The socket has to be a perfect tight fit on the bolt as otherwise it may round off, which then becomes a nightmare. Les Quote Link to comment Share on other sites More sharing options...
Gazzar Posted October 3, 2015 Share Posted October 3, 2015 Soak it for a day or two (plus gas?), then heat it. Then be aggressive with a hammer, you might want to spray some shock and freeze on it as well. Quote Link to comment Share on other sites More sharing options...
UdderlyOffroad Posted October 3, 2015 Share Posted October 3, 2015 Treat the 12 points bolts with care, windy guns are usually a bad idea. Wire brush the crud off, use a good quality socket (not one of those universal things). Drop the axle as per Les' advice, then get a breaker bar on the socket and use a jack to apply force to the breaker bar. The force of the jack will be counteracted by the spring force bearing down on the axle and hopefully the bolt will shift. Obviously you need to triple check that the jack is applying the force in the 'leftie loose-y' direction! Matt Quote Link to comment Share on other sites More sharing options...
Niamh Posted October 3, 2015 Author Share Posted October 3, 2015 Been a while since I did one, but if I remember right I disconnected the shock absorber and with the increased drop I was able to get straight onto the bolt head with an extension through the spring coil. I was thinking of jacking the chassis to get the spring to open a bit, currently it's just on axle stands it may round off, which then becomes a nightmare. Les All too true, trying very hard not to get to that stage. Niamh Quote Link to comment Share on other sites More sharing options...
Niamh Posted October 10, 2015 Author Share Posted October 10, 2015 Still not shifting! Going to cut off the outer part of the caliper so I can take the hub off and get better access. Niamh Quote Link to comment Share on other sites More sharing options...
Niamh Posted October 10, 2015 Author Share Posted October 10, 2015 And that makes things so much easier when the hest and penetrating oil can be applied where they'll do most good. Caliper off Niamh 1 Quote Link to comment Share on other sites More sharing options...
Sheffield Posted October 12, 2015 Share Posted October 12, 2015 I have just refurbished the two rear calipers, and I was lucky with the near side bolts. The hub seal has been leaking oil for a while and all has had a good soaking. They came out easily, which perhaps suggests repeated spraying of the caliper bolts with Plusgas starting several days in advance may help get them out. Quote Link to comment Share on other sites More sharing options...
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