 | Home > Maintenance & Modifications > Defender Rivets |
 
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| Oldowner Member Since: 26 Dec 2018 Location: South west Posts: 602   
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Those are steel solid head rivets, I think Avdel Monobolts were used as well.
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27th Dec 2019 9:25pm |
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| Dinnu Member Since: 24 Dec 2019 Location: Lija Posts: 3204  
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Thank you Oldowner.
They do not seem to be solid rivets. I managed to grind lengthwise the external part of the rivet, and the rivet is made of 2 parts. It actually looks like it is threaded, but when I tried to 'undo' another rivets, it just spun and the 'nut' did not come off, so perhaps what I thought where threads, could possibly be grooves to hold on the 2 parts together. I will get photos of the ground part when I get back to the garage. If they are monobolts, then there would be a hole for the mandrel through the head, no? |
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27th Dec 2019 9:49pm |
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| donmacn Member Since: 07 Nov 2017 Location: Nth Scotland Posts: 1829 |
Hi Dinnu,
Welcome to Defender2. Those rivets have a specific name which I can't remember, and despite searching, I can't find them. There's definitely some details about them on this site somewhere. I had to remove them to lift my rear floor. I did investigate what they were, and thought I might refit them myself, but they need specific tools and were just too expensive. I think they are used where there is access to both sides of the workpiece. In the end, I just used aluminium rivets as being the only practical option. If I find the thread I'm searching for, I'll link it here, but you've described them well: a ribbed 'female' section to grip the male rivet. EDIT - just remembered, they are 'huck bolts'. Google that and you'll get all the info you need. Donald 1994 Defender 300Tdi 110 SW - owned since 2002 - 230k miles and going strong (The 'rolling restoration' or tinkering thread: http://www.defender2.net/forum/topic58538.html ) 2000 Range Rover P38 4.0L V8 in the past.. RR classic - fitted with 200Tdi 1984 RR classic - V8 with ZF auto box 1993 Discovery 300Tdi not to mention the minis and the Type 2 VW camper... |
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27th Dec 2019 10:23pm |
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| miker Member Since: 13 Sep 2015 Location: Surrey Posts: 1758 
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They are known as huck bolts, and are a
 to remove and a to install! I replaced with rivets  |
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28th Dec 2019 12:49am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 16873 
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Huck bolts and Avdel monobolts are essentially similar but require (very!) expensive special tooling to install. Unless you have access to the correct tooling, forget it!
In both cases the fastener is passed through the parts to be joined, a collar is then placed over the stem of the fastener, and the setting tool (usually hydraulic) then grips the stem and tensions it at the same time compressing the collar, then shearing the overlength part of the stem. The rivet in the op's photo looks to me to be a normal iron rivet, which will probably have been set with hydraulic snaps in the factory but could be set easily enough with manual snaps. Those linked below may not be big enough but give the idea. https://www.chronos.ltd.uk/product-categor...ing-tools/ |
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28th Dec 2019 9:12am |
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| miker Member Since: 13 Sep 2015 Location: Surrey Posts: 1758
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The ones I've removed in the past definitely seemed to have a threaded/serrated portion and a collar
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28th Dec 2019 8:52pm |
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| Dinnu Member Since: 24 Dec 2019 Location: Lija Posts: 3204
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Thank you all for your replies. I searched Huck bolts, and yes, I think they are the one.
Since I only need to replace 12 of them, then i need to find a cheaper alternative as tools seem to be prohibitively expensive. Rivets seem to be the simplest option, although i also want to check how M5 button head bolts with anti theft nuts would look (would need to fill the head socket). 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing 2012 90 CSW, 2.2TDCI, Santorini Black |
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28th Dec 2019 10:16pm |
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| ARC99 Member Since: 19 Feb 2013 Location: North Yorkshire Posts: 1831 
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I may be wrong and I'm sure someone will probably know better if I am.
Those look like they part of the structure of the vehicle and need to be replaced with something of the same strength and resistance to corrosion. I don't think normal rivets would meet both criteria. Don't make old people mad. We don't like being old in the first place, so it doesn't take much to us off.
Richard |
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29th Dec 2019 9:54am |
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| donmacn Member Since: 07 Nov 2017 Location: Nth Scotland Posts: 1829 |
I certainly don't "know" whether you're right or not, but I did have that concern when replacing my floor.
So, I did think about fitting 'rivnuts' with M4 bolts at key locations, but on further consideration I thought that: a) so much of the strength of the Defender is in the chassis - the aluminium bodywork as a whole is a weak point; b) even if I had fitted rivnuts/steel bolts, then the alu. around them is 25 years old in some instances - if the strength was ever an issue, the alu. would just rip and tear anyway. Which is all to say that I thought about it, then rationalised myself out of it! Whether I'm right or wrong.... ? Donald 1994 Defender 300Tdi 110 SW - owned since 2002 - 230k miles and going strong (The 'rolling restoration' or tinkering thread: http://www.defender2.net/forum/topic58538.html ) 2000 Range Rover P38 4.0L V8 in the past.. RR classic - fitted with 200Tdi 1984 RR classic - V8 with ZF auto box 1993 Discovery 300Tdi not to mention the minis and the Type 2 VW camper... |
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29th Dec 2019 10:33am |
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| miker Member Since: 13 Sep 2015 Location: Surrey Posts: 1758
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Resistance to corrosion, in a defender?!
On the strength point, it's just the under tub supports, which sit on the chassis rail, the return from the sides sit on the supports, and the floor sits on the return. Everything's in compression, so no strength issues in my opinion |
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29th Dec 2019 11:44pm |
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| Dinnu Member Since: 24 Dec 2019 Location: Lija Posts: 3204
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I am also thinking that at this specific location, the stresses are not too high.
But i like to keep the visual appearance to be as true to the original design as possible. So to replicate the Buck Bolts as close as possible, i set about to do the following: 1. Purchased M5 extension nuts. 2. Turned the end down to 7.0mm, for a length of 7.3mm. 3. Recessed further the diameter to 5.75mm to create a stress point. 4. Drilled 5.5mm from hex side right to the recess. 5. Not done on this test part, but plan to zinc plate the machines surface for corrosion resistance. Will be painted anyhow. Machined part:  Click image to enlarge Using a pan head M5 screw, tightened until the nut sheared off. Screw is Allen head, but Allen socket can be easily filled up with a blob of epoxy before painting. Advisable to use a thread locker before assembly. Finished product: Click image to enlarge Click image to enlarge 1988 90 Hard Top, 19J Diesel Turbo, Shire Blue - Restoration ongoing 2012 90 CSW, 2.2TDCI, Santorini Black |
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3rd Jan 2020 10:14pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 16873
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M5 shear nuts would be much less work, albeit a slightly different shape!
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3rd Jan 2020 11:38pm |
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