Member Jonathan Kay Posted January 9 Member Share Posted January 9 1 hour ago, CtrMint said: WRT to replace the bolt, I can see they're caphead M10x20, grade 12.9, I assume any bolt with CoC meeting the spec will be acceptable? The Assembly Guide used to describe them as "special blue bolts". I don't know the correct specification. Jonathan Link to comment Share on other sites More sharing options...
CtrMint Posted January 9 Author Share Posted January 9 Thanks Jonathan, I found this old thread, Link to comment Share on other sites More sharing options...
DirtBuddha Posted January 10 Share Posted January 10 Mine had Loctite on and I just used a medium length 3/8 breaker bar attached to a socket and they came loose. Mine had hex bolts... as have all 4 of the Caterhams I've owned. I've not seen one with cap head bolts before, but the head type isn't the important thing, it's the grade as you have stated. Link to comment Share on other sites More sharing options...
7 wonders of the world Posted January 10 Share Posted January 10 CC may have opted for cap heads on the 620 possibly due to the increase in propshaft diameter restricting access to hex heads... I haven't seen one up close but just sumising... Link to comment Share on other sites More sharing options...
CtrMint Posted January 10 Author Share Posted January 10 (edited) I actually got the spec from my 420 build manual, the "Ikea" manual. The manual and bolts align, so I guess this has become the new standard. Edited January 10 by CtrMint Link to comment Share on other sites More sharing options...
StevehS3 Posted January 10 Share Posted January 10 My factory built Sigma has cap head bolts. Link to comment Share on other sites More sharing options...
aerobod - near CYYC Posted January 10 Share Posted January 10 My 2012 R400 also had cap head bolts. This is the current Caterham part: https://caterhamparts.co.uk/propshaft/651-setscrew-m10x1-caphead-propshaft-to-differential.html The ‘blue bolts’ label may be due to having medium strength thread locker on the bolts. I just clean the removed bolt threads and re-apply some more thread locker, no need for replacement bolts, as they aren’t stretch bolts going by the torque of 74Nm in the assembly guide (I’ve also seen 60Nm quoted). An M10x1 12.9 bolt can take a torque of 95Nm before it enters the plastic zone for stretch-bolt single use purposes. Link to comment Share on other sites More sharing options...
7 wonders of the world Posted January 10 Share Posted January 10 CC may have opted for cap heads on the 620 possibly due to the increase in propshaft diameter restricting access to hex heads... I haven't seen one up close but just sumising... Link to comment Share on other sites More sharing options...
7 wonders of the world Posted January 10 Share Posted January 10 The blur bolts were actually all blue... Can't recall the spec though 1 Link to comment Share on other sites More sharing options...
7 wonders of the world Posted January 10 Share Posted January 10 set of used ones here shows they were 10.9 grade Blue bolts Link to comment Share on other sites More sharing options...
ScottR400D Posted January 10 Share Posted January 10 30 minutes ago, 7 wonders of the world said: set of used ones here shows they were 10.9 grade Blue bolts I don’t think they’ve been used for years. My 2015 car had and the guide showed cap heads. Link to comment Share on other sites More sharing options...
CtrMint Posted January 10 Author Share Posted January 10 (edited) It's out 🙌 I'm not sure taking it out with the dedion in place was such a clever idea. There was a little too much contact with the dedion when trying to lift the nose of the diff and achieve the correct angle over the chassis structure at the back of the transmission tunnel. Maybe I should have removed the some of the hardware from the watts linkage etc, to provide a bit of play in the dedion. Next up is that pesky handbrake cable, hopefully with the diff removed I can get some mole grips on that adjuster. Any recommendations for getting the diff back in? Angles etc, should I lift the nose at 45 degrees etc. Also there's a breather pipe on the Ford diff, which is new to me, any gotchas etc with that? Thanks Edited January 10 by CtrMint Link to comment Share on other sites More sharing options...
StevehS3 Posted January 11 Share Posted January 11 I left the original carrier in place and lowered the old diff out of it. I don’t remember the replacement requiring any specific angles etc for re-fitting. It just seemed to slot straight in. As you say, I wonder if the Watts linkage is restricting the space. Might be worth disconnecting it to see. Link to comment Share on other sites More sharing options...
Englishmaninwales Posted January 11 Share Posted January 11 12 hours ago, CtrMint said: …Also there's a breather pipe on the Ford diff, which is new to me, any gotchas etc with that? Thanks Ford diff breather - these are very brittle and snap easily, so care on refitting the diff. They are generally unavailable, although found one on eBay. R+R can supply a re-manufactured replacement. As my car is only for track use, I attached a vertical pipe to a catch tank in the boot. Link to comment Share on other sites More sharing options...
CtrMint Posted January 11 Author Share Posted January 11 Thank you for the warning. As I've now 2 complete ford based diffs, if I screw up fitting one I could steal from the other 😀 Steve, don't forget this is the ford diff, so no carrier, and slightly bigger than the BMW housing on the 420R. Last night I spent a tonne of time Googling grease for the drive shafts on the diff side. I'm pretty sure that grease should be used during fitment, it was already on the splines and bearing surface during removal, but I can't find specs to get get things absolutely correct. Can anyone recommend the type of grease for the splines, the bearing face (not sure if thats the correct term) and also the outer seal on the diff if required. Thanks Link to comment Share on other sites More sharing options...
John Vine Posted January 11 Share Posted January 11 This is what the text-rich Assembly Guide says: I would use a general-purpose grease such as Castrol LM. JV Link to comment Share on other sites More sharing options...
CtrMint Posted January 11 Author Share Posted January 11 Thanks JV, not too specific then. Link to comment Share on other sites More sharing options...
CtrMint Posted January 13 Author Share Posted January 13 Could I possibly inquire as to how much oil the Ford diff housing needs, my Caterham manuals covers the BMW Titan setup. Not sure if a my Drexler vs, Tracsport or Titan makes a difference. Also this might be a silly question, but can I fill through the drive shaft openings. I noticed when I removed the shafts with the car on stands I didn't loose any oil, though tipping the diff when removing resulted in egress. Thus can I fill that way, it would be, I think easier and faster. Thanks Link to comment Share on other sites More sharing options...
Benton Posted January 13 Share Posted January 13 Taken from a Facebook thread sometime from Ollie Stewart Road and Race Transmissions Link to comment Share on other sites More sharing options...
CtrMint Posted January 13 Author Share Posted January 13 Thank you Benton Link to comment Share on other sites More sharing options...
22daz Posted January 21 Share Posted January 21 Mark, I did this job last year to fit a Tracsport. Other than an occasional CPW whirr under certain loads it has been superb. Absolutely no knocking and clunking even pulling out of tight junctions. I took the ears off the end of the Dedion and pulled the driveshafts out as a big lump leaving the Dedion ends bare. The propshaft bolts are thread locked in and that’s how I replaced them, but with new bolts. For me there was no chance of removing them with a socket and bar. The prop just wanted to move and I was concerned I’d just round them off making the job impossible. A Milwaukee impacter with a long extension to negate the angle took them off. I think it rattles the threadlock and breaks them loose. Quite a relief. 22daz Link to comment Share on other sites More sharing options...
7 wonders of the world Posted January 22 Share Posted January 22 Fill the final drive to the level plug with the car on the ground Worth replacing the Allen head OEM. plug with a magnetic hex head version it makes accessing it in the car massively easier. Link to comment Share on other sites More sharing options...
7 wonders of the world Posted January 22 Share Posted January 22 M20 x 1.5 is the size to look for on ebay Link to comment Share on other sites More sharing options...
CtrMint Posted January 27 Author Share Posted January 27 I managed to drive the 620R for a few meters around the cul-de-sac today, no more than 15 to 20mph. It was a big improvement in noise, I didn't spot any clunks and no apparent noise from the final drive, which would have been apparent on the previous diff even at slow speeds. So reassuring it wasn't my Sadev. I have no idea why the final drive fitted to the Tracsport was so bad. The 620R is back on axles stands as I'm trying to get the Dedion properly aligned. Link to comment Share on other sites More sharing options...
7 wonders of the world Posted January 28 Share Posted January 28 Think you need to look to who built the final drive for the answer there, Link to comment Share on other sites More sharing options...
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