Mo Murphy Posted January 13, 2017 Share Posted January 13, 2017 Morning all, Is there a way to discern if Range Rover front brake calipers have imperial or metric mounting bolts without removing them ? I've always found myself that the imperial bolts have a hex head whereas the metric bolts seem to be 12 point. Would this be a reliable method of telling them apart ? (I do know, by the way, that that caliper mounting holes are different sizes but I hope to avoid having to remove them needlessly) ? Second question for the panel ... Is it safe to use Range Rover twin line front calipers on a 90 ? How do you bridge the twin ports ? Anyone got any pics of it done ? You may have guessed that I've been offered a pair of new Range Rover front calipers to replace mine which are now in need of replacement ? Mo Quote Link to comment Share on other sites More sharing options...
rtbarton Posted January 13, 2017 Share Posted January 13, 2017 Metric bolts will have something 12.6 or 8.8 stamped on the head somewhere, Imperial will have a letter, most likely R or S (BSF threads) or a series of dashes arranged radially Google "Bolt head markings" Quote Link to comment Share on other sites More sharing options...
pete3000 Posted January 13, 2017 Share Posted January 13, 2017 Push a socket on, if the metric one is a tight fit, it's metric. If the imperial one is a tight fit it's imperial, , Coat----->Door. The 12 point is most probably Metric. Or more seriously if you find the cat no stamped on the hub swivel pin assembly the caliper bolts up to would the part no give it away i.e RTC (metric) ESR or just a number (imperial). Then find the matching bolt. or am i off track? BTW from a quick search ABS equipped seem to be metric and non ABS use a mix. Quote Link to comment Share on other sites More sharing options...
Maverik Posted January 13, 2017 Share Posted January 13, 2017 If the bolt head is corroded I doubt you'll be able to tell by socket size or labelling. I carry at least a set of each in my stock these days, it doesn't take much for the heads to become corroded and unusable (not quite found a way to protect them properly yet). Its blatantly clear once its out, the imperial thread is pretty course compared to the metric equivalent... Quote Link to comment Share on other sites More sharing options...
rtbarton Posted January 13, 2017 Share Posted January 13, 2017 UNF threads are finer than the standard metric, UNC may be coarser, but I think fine metric is finer than UNF. Thread tables are the best way to compare threads. A thread gauge is the only sure way to tell what thread you have in your hand. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted January 13, 2017 Author Share Posted January 13, 2017 Thanks chaps, looks like I'll have to pull a bolt out. Mo Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted January 13, 2017 Share Posted January 13, 2017 I think you are quite right to judge it by the 6point/12point method, I have never seen a metric with 6 points and never seen an imperial with 12 points, and I have messed quite a lot with old RRC's. Of course someone could have fitted 6 point metric bolts instead of the 12 pointed ones from the factory. But if the swivel ball is also the old imperial kind (6 bolts instead of 7) then you should be pretty safe 2 Quote Link to comment Share on other sites More sharing options...
pete3000 Posted January 13, 2017 Share Posted January 13, 2017 1 hour ago, Maverik said: If the bolt head is corroded I doubt you'll be able to tell by socket size or labelling. I carry at least a set of each in my stock these days, it doesn't take much for the heads to become corroded and unusable (not quite found a way to protect them properly yet). Its blatantly clear once its out, the imperial thread is pretty course compared to the metric equivalent... Indeed, i was only having a jest. As an aside though I often use my worst (best) stanley socket set to hammer onto corroded bolt heads of the opposite scheme to get them out. i.e not the next mm size down just find a close A/F match. Before next trying the mole grips, chisels, grinder then the drill. Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted January 13, 2017 Author Share Posted January 13, 2017 Thanks Soren, I knew playing with old axles would pay off one day ? Mo Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted January 13, 2017 Author Share Posted January 13, 2017 Indeed Pete, taken in jest ? Mo 1 Quote Link to comment Share on other sites More sharing options...
miketomcat Posted January 14, 2017 Share Posted January 14, 2017 Sorry to upset but I have both metric and imperial bolts in stock as the 110 is imperial (yes it is that old) and 45 is metric both have 12 point heads. The only way to check for certain is to remove a bolt. As to plumbing it is possible to fit the entire twin line system including servo. I have the disco twin line system on 45 but the bias valve needs to be a 90 item. You could link the brake line ports this used to be done on minis when fitting metro 4 pot calipers. You could buy a braided hose that had a link pipe to the second port. It will give you longer pedal travel though. If it was me I'd just use the correct calipers there is no real advantage of disco/rangey calipers over 90 ones. If you want an upgrade then 110 calipers are what you need. Mike Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted January 14, 2017 Author Share Posted January 14, 2017 Hmmm, food for thought indeed. I didnt know about longer pedal travel. Thanks for that, Mike. Mo Quote Link to comment Share on other sites More sharing options...
landrover598 Posted January 14, 2017 Share Posted January 14, 2017 One solution for twin pipe plumbing i tried many years ago, worked fine. Quote Link to comment Share on other sites More sharing options...
miketomcat Posted January 14, 2017 Share Posted January 14, 2017 I have seen similar to daves but with the tee on the chassis end and two hoses to the caliper. To be fair on minis the longer travel wasn't much and certainly not a problem so I doubt it would be a problem on a 90. Mike Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 14, 2017 Share Posted January 14, 2017 Trying work out why longer travel? I mean compared to other 4 piston callipers. Quote Link to comment Share on other sites More sharing options...
miketomcat Posted January 14, 2017 Share Posted January 14, 2017 Mini was due to swapping from two pistons to four. 45 has longer travel than our 110 but that could be because it's the whole disco system on a 90 pedal box. On reflection your right, assuming range rover and 90 pistons are the same size as they are both 4 pot. Mike Quote Link to comment Share on other sites More sharing options...
Maverik Posted January 14, 2017 Share Posted January 14, 2017 My 86 90 has the ones on the left, everything else post 1990 I've ever worked on has the ones on the right. Quote Link to comment Share on other sites More sharing options...
Soren Frimodt Posted January 14, 2017 Share Posted January 14, 2017 1 minute ago, Maverik said: My 86 90 has the ones on the left, everything else post 1990 I've ever worked on has the ones on the right. yep there are 2 different 12 point versions, however I'm pretty sure they are both metric? Just one fine thread and the other course? I could be wrong though, have never measured the pitch of either of those two. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted January 14, 2017 Share Posted January 14, 2017 3 hours ago, miketomcat said: Mini was due to swapping from two pistons to four. 45 has longer travel than our 110 but that could be because it's the whole disco system on a 90 pedal box. On reflection your right, assuming range rover and 90 pistons are the same size as they are both 4 pot. Mike Ta mike, was just making sure I wasn't missing something Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted January 14, 2017 Author Share Posted January 14, 2017 1 hour ago, Maverik said: My 86 90 has the ones on the left, everything else post 1990 I've ever worked on has the ones on the right. All caliper bolts from the start of production of 110s and 90s had metric bolts. Mo Quote Link to comment Share on other sites More sharing options...
miketomcat Posted January 15, 2017 Share Posted January 15, 2017 Just had a rummage through parts catalogues. It would appear 90/110 are metric upto 86 then they went metric fine. Discovery had imperial to start then went metric fine. So on that basis if the axle is the larger rounded mushroom type half shaft aka range rover axles it will be imperial. I know they fitted metric axles to rangies as well these should have the later separate drive flanges. Mike Quote Link to comment Share on other sites More sharing options...
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