Bob L Posted September 11, 2012 Share Posted September 11, 2012 Just had the O/S rear damper bolt shear where it enters the De Dion tube ☹️ It literally gave way on a straight (no humps) road at 20 MPH. There is nothing to grip to enable removal of the remaining bolt and coaxing the remainder of the bolt out seems a PITA from previous threads (sheared flush with the tube). On top of this the bolt on the N/S appears very slightly bent. The tube is series 3 and appears totally undamaged but I’m thinking of removing the dampers from the lower welded sleeve position to the ‘through the tube’ positions with the CC bolts for this setting. I believe the lower positions on the Series 3 DDT are a concern (my thanks to Ian B et al’s substantial research and reporting on this issue) and only in play to accommodate the progressive damper / spring arrangement that was slightly longer than the previous set up. Questions: 1) I have adjustable std Bilstien dampers that appear in good order but they are now 13 years old. Assuming I can get the correct ride height, any issues in keeping these in play. 2) If not, what dampers / springs are recommended. The 7 is a 1999, 1.8 Supersport on 13’’ wheels, Toyo 888’s. Only been on track twice but I may get brave enough to do more. Owned from new so complete history known, no accidents or curbs and driven like a tart 😳 Need to dip in and out so apologies to late responses. Link to comment Share on other sites More sharing options...
Z3MCJez Posted September 11, 2012 Share Posted September 11, 2012 Ref: your Q1 - I have standard Bilsteins that were on my car for 2 years and have now been stored for 2 years. You'll need to use your existing platforms (but if you're changing your dampers, that won't be an issue!). Although others will have more knowledge, I've changed dampers and springs on all of my tintops more frequently than every 13 years, but I guess it's not solely time driven, but mileage related in part too. My springs / dampers are available for much less than CC charge! Blatmail if you are interested. Jez Link to comment Share on other sites More sharing options...
Wrightpayne Posted September 11, 2012 Share Posted September 11, 2012 Do a search on dedion tube failures. Might be prudent to change if it's from a certain era. Linky here You would need different dampers to use the through tube holes. Might alter the handling too. Ian Edited by - Wrightpayne on 11 Sep 2012 22:44:22 Link to comment Share on other sites More sharing options...
Bob L Posted September 12, 2012 Author Share Posted September 12, 2012 Jez – Thanks but I have a spare new set of non adjustable Bilstien’s that came with the original kit. Ian - Thanks yes, I read through all the horror stories. The welds are intact with no damage visible elsewhere, I’ll get a better look once both dampers are removed. I would just feel safer using through the tube mountings and seen threads where some guys had reverted to this method but I believe they changed the dampers for something more appropriate. As mine seem fine but now 13 years on, I’m not opposed to changing and would welcome views on recommended. I’m surprised the bold has sheared where it has and would have thought the welded tube itself would be the potential weak point. Link to comment Share on other sites More sharing options...
charlie_pank Posted September 12, 2012 Share Posted September 12, 2012 Obviously at some point there's been undue force on the suspension to cause the failure that you've had. It was enough to shear the bolt and the mounting point stayed intact. This demonstrates that the weakest point in your setup is the bolt, but you want to move to the other (untested) mount points because other people have had failures in the lower mount points. This doesn't make logical sense! Edited by - charlie_pank on 12 Sep 2012 10:54:41 Link to comment Share on other sites More sharing options...
Bob L Posted September 12, 2012 Author Share Posted September 12, 2012 My thoughts are the bolt sheared through fatigue, nothing sudden. As you can view from my treads, it has been driven carefully and never curbed, not even the rumble strips on the 2 occasions it has been on track. It failed at low speed on a straight road. The only difference was that SWMBO was a passenger. I very really run with 2 up so the additional weight could be the tipping point but for the sake of my marriage I must stress that the missus is quite slim and it is likely the failure would still happen anyway – just a question of when. The existing welded sleeve now has a sheered bolt stuck in it and this is unlikely to budge from the threads viewed where others have tried. Apart from that this is a known week point on 1999 DDT’s so why bother with this point at all. The DDT appears in good condition and has the alternative mounting points through the DDT tube itself, which I believe is stronger and no failures around this point reported. Again I believe some have taken this route for similar reasons but the dampers may well need to be changed to a shorter type. I believe I have 4 options: 1. Try and remove the remains of the bolt and reconnect as is 2. Replace the DDT for an upgraded version from CC which is probably the best overall option 3. Use the alternative mounting position and adjust the existing dampers to the correct ride height (if possible) there only seems about 30mm difference. 4. As above but change the dampers to something more suitable if 3 above does not work Link to comment Share on other sites More sharing options...
charlie_pank Posted September 12, 2012 Share Posted September 12, 2012 Quoting Bob L: My thoughts are the bolt sheared through fatigue, nothing sudden. I guess that's how most of the DD failures happen too, but yours seems to have survived enough fatigue to destroy the bolt! Quoting Bob L: The existing welded sleeve now has a sheered bolt stuck in it and this is unlikely to budge from the threads viewed where others have tried. I'm sure a local machine shop could get it out with no problem if you took them the DD tube. Quoting Bob L: ... but the dampers may well need to be changed to a shorter type. They WILL need to be changed Quoting Bob L: 2. Replace the DDT for an upgraded version from CC which is probably the best overall option There's nothing wrong with your DDT apart from the fact there's a bolt stuck in it - this is probably less expensive than getting new springs and dampers, but still more expensive than getting the old bolt out. Quoting Bob L: 3. Use the alternative mounting position and adjust the existing dampers to the correct ride height (if possible) there only seems about 30mm difference. If it were possible without seriously compromising the handling, CC would have done it instead of making new mount points. What is 30mm as a proportion of the total damper travel? Quoting Bob L: 4. As above but change the dampers to something more suitable if 3 above does not work Ker-ching! - but maybe ok if you need new dampers anyway. Given that you'd have to take the DDT out to replace it anyway, it's probably worth getting it out and having a go at removing the bolt (apply heat/drill/hammer in a torx bit/take to machine shop etc....) before you buy another one. Edited by - charlie_pank on 12 Sep 2012 12:52:39 Link to comment Share on other sites More sharing options...
MADMALC Posted September 12, 2012 Share Posted September 12, 2012 If you do get the bolt out and use the tube again I would suggest having the strengthening fillets fitted as well. Link to comment Share on other sites More sharing options...
elie boone Posted September 12, 2012 Share Posted September 12, 2012 If a 1/2" bolt sheares i would think it was not done up correctly, or there is a sharp edge on the DD tube mounting hole, the reaining piece schould just be pushed out. The reason for the lower damper mount was that Caterham started to use progressive springs Link to comment Share on other sites More sharing options...
Bob L Posted September 13, 2012 Author Share Posted September 13, 2012 The more I think on this (taking your comments into consideration) the more I’m erring on a new DDT. If for nothing else for the time it will save and the chance to upgrade to a more robust version. My thanks to you guys for taking the time to pen your views – much appreciated Link to comment Share on other sites More sharing options...
charlie_pank Posted September 13, 2012 Share Posted September 13, 2012 Steps to replace DDT: 1. Remove wheels 2. Remove brake pipes 3. Remove calipers 4. Remove DD ears, hubs and driveshafts 5. Release dampers from DDT 6. Remove radius arms 7. Slide DDT out of a wheel-arch 8. Slide new DDT in 9. Follow steps 1-6 in reverse 10. Bleed brakes Steps to re-use DDT: 1. Remove wheels 2. Remove brake pipes 3. Remove calipers 4. Remove DD ears, hubs and driveshafts 5. Release dampers from DDT 6. Remove radius arms 7. Slide DDT out of a wheel-arch 7a. Get machine shop to remove sheared bolt 8. Slide DDT back in 9. Follow steps 1-6 in reverse 10. Bleed brakes Link to comment Share on other sites More sharing options...
Paul McKenzie Posted September 13, 2012 Share Posted September 13, 2012 Quoting elie boone: If a 1/2" bolt sheares i would think it was not done up correctly, or there is a sharp edge on the DD tube mounting hole, the reaining piece schould just be pushed out. The reason for the lower damper mount was that Caterham started to use progressive springs Elie, They were using progressive springs before they took the (retrograde 😳) step to use the 'tacked on' lower damper mount. My '96 car has progressives and the 'through the DD tube' mounting Link to comment Share on other sites More sharing options...
John Alston Posted September 13, 2012 Share Posted September 13, 2012 What was the real reason for Caterham to change the DDT damper mounting then ??? Link to comment Share on other sites More sharing options...
Bricol Posted September 13, 2012 Share Posted September 13, 2012 I think you an leave most of that list attached to the car - brakes, driveshafts etc - just disconnect or un-tie from the tube and support as required while you remove/replace the tube. Mav might be the one to ask, having done it in an Italian hotel car park in the shadow of some nice mountains. Nicest place I've welded on up too 😬 or rather Bri Link to comment Share on other sites More sharing options...
elie boone Posted September 13, 2012 Share Posted September 13, 2012 Paul, 😶🌫️ the only progressive springs i have seen where on the lower mounts so i guessed it was from the lower mount on they used the progessive springs. Link to comment Share on other sites More sharing options...
Paul McKenzie Posted September 13, 2012 Share Posted September 13, 2012 Quoting John Alston: What was the real reason for Caterham to change the DDT damper mounting then ??? No idea, it seemed a daft idea to me - you don't need an engineering degree to see that it's structurally inferior, and I can't see that there would even be any manufacturing cost reductions Link to comment Share on other sites More sharing options...
charlie_pank Posted September 13, 2012 Share Posted September 13, 2012 Quoting Bricol: I think you an leave most of that list attached to the car - brakes, driveshafts etc - just disconnect or un-tie from the tube and support as required while you remove/replace the tube. Mav might be the one to ask, having done it in an Italian hotel car park in the shadow of some nice mountains. Nicest place I've welded on up too 😬 or rather Bri When I did it a couple of months ago I found it hard enough to get the tube out with my list removed. It might be possible without, but far easier as you need to release the ears anyway to just pull the shafts right out. Besides, the point was that bolt removal is hardly more hassle than tube replacement. Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now