Rivnuts Views

[CtrMint]

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

 

[7 wonders of the world]

I don't see why you had to remove the tunnel top and disconnect the compensator...? simply back the white adjuster right off and you can get one end off the calipers, done it on several cars with no problem.

[paul richards]

Rivnuts could be used, but the plate won't sit perfectly flat i.e. there will be a small gap because of the "head" of the rivnut. However I doubt this would be a problem. Having said that my car is like Triggers Broom with all the work ive done and in 20 years I've never found the need to remove the plate. An alternative would be to use self tapping screws. 

[Wrightpayne]

Ditto - never been off on mine - engine and diff been out several times. I wonder if the later electric welded chassis (as opposed to the proper bronze fillet welded chassis) is different?

[ScottR400D]

I don't think the chassis type makes much difference. Rivnuts or screws could be used but they wouldn't fit as flush as rivets. 

As others have found there's not too much reason to have to get in there, IME. 

[Philip L Anderson]

I have used a variety small and large rivet nuts on my Seven as well as on my other vehicles and around the shop. Its not hard to do if you have a good tool. A spinning type is the best but it it requires a lot of working room which you probably don't have. The the type that looks similar to a pop rivet gun is works well and is much better in small spaces. For really tight space one can use a the nut and bolt type that uses a coupe of wrenches, but takes a little practice to set the nut properly. 

[John Vine]

Like others, I'm having difficulty understanding why you need the plate to be detachable.  However, if you really need access in the future, self-tappers with a broad, flat head will do the job.

JV

[Richard Price]

Whilst I don't see the need to remove the plate, if you do want to use to nut it want to avoid the issue of the plate not sitting flush, then use countersunk to nuts.

https://www.ebay.co.uk/itm/RIVNUTS-THIN-SHEET-RIVET-NUTS-COUNTERSUNK-STEEL-THREADED-INSERTS-M4-M5-M6-M8-M10-/182064840166?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=710-127635-2958-0

[CtrMint]

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.

[Neil220]

I worked at Nissan for over 20 years and Rivnuts were used in many applications. 

However, the body panels were designed  with recesses to allow the rivnuts to sit flush on the panel. 

One example was the door courtesy light switches.

[Dave7vx]

I did this to mine, Trident Racing Supplies, page 98 of their catalog, 4mm flush head steel rivnuts, I did mine all the way to the front bulkhead for easy access to all the tunnel top. Spend a few quid on dome head stainless capheads and it looks good too.

[StevehS3]

I think the metric chassis is a bit different in this area. I have removed the cable at each caliper end by backing off the adjuster as suggested but changing the cable, as I need to do, might be a different story. The passenger side retainer for the outer is barely reachable. 

[CtrMint]

Thanks for that, excellent catalog too!

[ChrisC]

Having just replaced my prop on a 2020 S3 chassis, I can say the handbrake cable removal from the diff carrier did require the disconnection of the cable from the handbrake.  It was simple, just pull the pin holding pulley bracket to the handbrake.  Obviously this wasn't needed to remove the cable from the calipers that could be done with the adjuster.  I found even with the handbrake cable disconnected from the calipers, there wasn't enough slack for the outer cable to clear the diff bracket.   Not sure if the dimensions have changed, but the adjustment nut is no longer white (as it has been on all my previous cars), new supplier or specification change, I don't know.

I have never needed to remove the prop cover plate in all my years of Caterham ownership.  I suspect it would only be needed for chassis work or refurbishment.  Also is it a stressed member, like the side panels of the trans tunnel?  I thought the trans side panels where the only stressed panel left on the modern seven, but happy to be correct.  Given the diff mounts can fail with higher powered cars, and are strengthened in 620/R500 I can't help thinking it's an area I would leave alone.

[StevehS3]

Chris, does your car have a riveted plate over the area I have outlined in blue (mine does). The part I struggle with is getting the cable into the bracket shown by the arrow [with the diff, prop and plate in-place].

[ChrisC]

That photo is my car, and when I removed the prop recently the cover plate was fitted.  The green arrow is pointing to the outer cable location point for the LHS where there is no corresponding bracket on the diff carrier.  The opposite side cased my lack of clearance hampering removal (from the diff carrier) before dropping the diff. 
 

I have only ever changed one handbrake cable, the diff was out but the cover plate was fitted.  I suspect fitting one with the diff in position would only be possible if the prop was disconnected, even then I might be tempted to remove the hub/driveshaft assembly each side for access.  I also suspect you would have to remove diff bolts as you go to gain access.   The green arrow bracket would be my last point for release when removing, and the first for reassembly. 
 

[CtrMint]

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. 

[Colin Heseltine]

I have used Thin Sheet Rivnuts on lots of jobs, but not on the Caterham.  They only need a very lightly countersunk hole and will sit flush to the surface.

Colin

[ScottR400D]

It's interesting how things seem to vary from car to car. When I had my diff out, after disconnecting the cable from the O/S calliper I had no trouble feeding it back up into the tunnel until the inner was through the diff carrier bracket allowing its removal. 

From memory I did release the cable from the N/S tunnel bracket too but it was all very simple as was its replacement. 

[ChrisC]

I found a photo which shows how much of the outer cable is through the chassis bracket, before the cover plate was fitted.  It shows how much of the cable has to be released on a car fitted with the 2020 cable, don't forget if you have a BMW diff it also has to be released from the bracket on the diff carrier in the boot. 
 

We all need to remember these cars are constantly changing, I spotted over ten changes from my 2020 car to a recent 2021 420R kit I looked at.  Any of these changes can change a maintenance procedure, but the good news is, it does mean every days a school day 

[StevehS3]

Thanks for this Chris. I think it is the same as my 2011/12 K series. After about an hour of trying I managed to get the cable into the holder circled in blue without removing the cover. As Mark said, because of finding a kinked cable I now want to replace that and have visibility of the cable run. For this I will need to remove the top plate - which takes us back to Mark's original point about whether to use rivnuts.

 

[Beagler]

I removed the plate to fit a new cable. I will fit rivnuts and a thin foam seal so there is no gap. The improved access is worth it for me.