CtrMint

I've finally had chance to run the 620R to Ramsey and back over the Mountain Road. Conditions were cold and damp. I swapped the wheels/tyres to ZZS from my 420R. Ambients temps in Onchan according to the BBC weather app are 10c so I suspect less than 8c on the Mountain, maybe lower with wind chill, and it is windy up there! I drove away from the house with the car good and hot, having let it warm through, at the end of the day it's been over cooling and not over heating. Temps were around 90c, the fan did kick in at a set of traffic light in Onchan, but quickly went off. Driving too and from Ramsey the temps ranged between 80 and 90c. The drive didn't included any hard acceleration and nothing over 4k. I did reach around 90mph on the return run, which is usually where I see the 420R temps dip, I guess the wind direction is more noticeable. Temps still didn't dip below 80c. I appreciate that's not track driving, but it's a huge improvement.

Err, ignore me,,, I think! The handbrake warning light is also the brake fluid light, and since I have the ears off, and brake fluid drained it's going warn. Though not sure why I'm not getting a difference on the microswitch terminals.

Hi, I've fitted a new handbrake cable today as part of my diff replacement project. For ease I took the handbrake lever out, however having refitted everything, I've noticed the handbrake warning light is on when the engine isn't running. It's not been started, though I don't think it makes any difference. I've checked the resistance across the handbrake microswitch terminals, both in the open and closed position, but it remains open circuit. I'm assuming that's not correct? I can't see how I've damaged it, so I'm a bit baffled as to what's wrong. Any advice? Thanks Mark

I'll try and get another video to show the expansion bottle connection, though probably over the weekend. Pretty sure it's a 95/98c stat. It didn't seem to cause any issue when testing, the rad was hot when the fan kicked in too. Even if it's slightly early I guess it will help keep the temps on the safe side, rather than over hot etc. If it's dry over the weekend, I'll run the car up the Mountain it will be around 7/8c or up there, and at speed it will be a good test.

This one is awful, you are warned ;-) Trying to get the thermostat housing.

Trying to document the modification has not been easy, as you know it's pretty tight under the bonnet. I've captured a video of the part which I guess is of most interest. The car also now has a new standard thermostat housing with a metal insert to reduce the pressure on one of the ports, plus new hoses all round and a joint some where under the plenum. A new 95c thermostat has also been fitted.

For completeness, I thought it worth mentioning my 620R has now had it's cooling circuit revised, though sadly due to some biblical rain testing has been prevented. More to follow.

CC parcel arrived this week. New handbrake cable and the 5 speed gearbox spacer. Not sure if I will be inclined to work on the 420R this weekend. I did tell myself to take my time over the process and enjoy it. It's pretty cool too, reminds me of my original build.

I think people are missing the point that I was attempting to make life easier, so that I could easily see the seating of the cable as it routes down the tunnel. This is partly based on the fact I and also Steve have suffered kinks in the cable. I don't presume to do everything correctly, and wonder whether some of the issues I face are down to my lack of mechanical knowledge and experience. Improving my ability to see/review the cable routing makes sense. I don't have tens of years of experience, running X number of Sevens, and I'm on a steep learning curve, every little helps. I didn't even presume Rivnuts were the correct solution.

Thanks for that, excellent catalog too!

I wouldn't say I need too, I just thought it would provide easier access to the handbrake cable and tunnel. I appreciate you can reach everything with it in place, but it isn't that easy.

Afternoon All, Does anyone have any experience with Rivnuts, specifically relatively small sizing, say M4 and M3 if available? I'd be interested to hear your views. Having removed my handbrake cable while dropping my diff I'm considering whether there is a better solution to the rivet fixings used to secure the transmission tunnel plate that sits over the end of the prop. I figure it would be a lot easier to have the plate secured with a removal fixing so that the plate can be lifted when access is required. Cheers

Hey, Yep it crosses over too. Your location sounds very similar too, sort of helpful to know it's not something isolated to my car and possibly something daft that I've done.

Youtube based slides deck

Quick update. Old diff is out, drained and the back plate removed. I've then wiped the diff internals down for inspection, though I openly admit I'm not sure what I'm looking for in terms of faults. It certainly looks ok, i.e. nothing loose or broken. The oil had an interesting finish to it, certainly some traces of metal, but nothing significant. I've run a magnetic pick up tool through the oil and nothing notable. I also put a magnetic parts tray under the drain pan, again nothing amazing. I do admit I'm not really sure how the oil should really look. I'll upload a slide deck to Youtube rather than spam images to here. Would love to hear opinions. It wasn't all good news though. Removal of the shafts etc all went well, and once I committed to disassembling the handbrake assembly (thanks btw) I got the diff out with ease. Unfortunately I found a nasty kink in the handbrake cable and some heavy marring and compression on the plastic outer. Not ideal, so I've very reluctantly opted to stop, and source a replace cable. Very disappointing as I'd spent a long time preparing for this weekend, aim being to get the new diff in and the car built. I'm not sure why the damage occurred to the handbrake cable, I've never had any issues with it during use, and it was balanced during its Manx IVA. Bit of a head scratcher.

Thanks both, ended up pulling the pin and removing the entire assembly. I found the cable had a kink and damage to the plastic sheath. To prevent an potential balance issue, I've opted to replace the cable. As result the project has been delayed.

Guys, I have the tunnel cover up, whats the best strategy for disconnecting the handbrake cable Thanks

hmm, I guess I'm being too light, probably a bit more force is needed. I Will be spending the entire day on it tomorrow, will give it another go. Thanks

yes, the brake assembly is free from the car itself, so I can move it towards the diff hanger releasing the tension etc.

I made some good progress this evening. The offside driveshaft is now out, along with the ear and the brake assembly which I removed from the dedion as one piece. The driveshaft looks unmarked and in good condition, as do the bearing on the ear. The one thing I can't figure out is how to disconnect the handbrake cable from the brake assembly. It's probably super simple, but I just couldn't unclip the rectangular eyelet from the hook on the brake. Could someone point me in the in right direction please. Thanks

Thanks for the input all. I found a FAQ on the Road & Race website that recommended the Redline MTL GL4 so went with that.

Hi, I'm going to replace the (5 speed) gearbox oil while I've got the 420R in bits. As with many things, this has resulted in a bit of a dilemma. My owners manual says the following; 5spd All models exc 160/165. COMMA EP 75w80 GL4 Caterham 6spd COMMA EP 75w80 Mineral GL 4That seems simple, however, with my kit, CC sent mineral as shown. So I'm left wondering what to order? Any recommendations, as mentioned its the Mazda 5speed. Thanks

think I missed that option. Pulling the ears off the dedion right? that would have allowed the drive shaft nuts to stay in place? Ahh well, will order them, £15 each isn't going to break the bank, and as you say they are a bit critical.

Drive shaft nuts, the ones which are handed should they be reused? There is no signs of abnormal wear etc, but they are a heavy version of a nyloc? So I'm wondering if they should be replaced. Thanks

Thanks all, appreciate the comments trying to save me time. I'm pulling the entire rear out, as I've also decided to upgrade the suspension too, so not just the brake lines.