Upper Seatbelt/harness Mounts

[Guest smartfazer]

Hi all,

 

Do I have to captivate the nuts on the rear/upper seatbelt anchorage points?

 

I have the 2B with the round cross tube that GBS welded little tubes through.

 

Am I right in thinking that if you can get a spanner to the nuts, they don't have to be captivated?

 

Thanks.

 

Steve

[thespannerman]

Used to require captive nuts for SVA. But GBSC never have captive nuts on there show cars. I have welded on captive nuts with nyloc nuts as lock nuts onto clip on eye bolts, never come undone. SVA used to say that when the main belt retaining bolt was removed the fixing plate should not fall away from the mounting point (comercial belt mount plates ussually have a small hole for a rivet or bolt to secure them to a monocoque.

[Guest smartfazer]

Thanks Spannerman, I am going to weld on some captive nuts.

 

Was reading through the IVA manual last night, the chapter on Seatbelts and..............

 

B*gg*r, b*gg*r, b*gg*r, I should have read it more thoroughly before. I had welded captive nuts on all the lower anchorage points using M10 HT nuts and bolts and they need to be 11mm minimum or 7/16" in old money!!!

 

I wanted to keep things simple by using metric throughout, but it seems the industry standard for seatbelts is 7/16".

 

Fortunately, I had captivated the nuts on removable plates, so I have spent the afternoon removing the welded nuts from these. It's good also to see how well my welding had penetrated.

 

Ho hum, 7/16 UNF nuts and bolts on order.

 

Steve

[megadodo]

No, you don't need capitve nuts except in a box section wher ther is no access to the nut. The latest revision dosen't even mention captive nuts, its all about mounting point strength and bolt grade etc. Robin Hoods are done under visual inspection rules so photgraphic evidence of all bolts and nuts that you can't easily see must be given. The previous revision DOES mention captive nuts BUT that was where damage may be caused to the mounting points in ensuring they are tight enough and to box sections. As always the rules may well be interpreted differently by different test stations. It is perfectly acceptable to have access by trim removal as per the 2B, not sure about the Zero.

[agent_zed]

Hi

for my SVA in 2007 my top mounts didn't need captive nuts. Just got normal nylocks on the bottom poking out. only used captive nuts on the one side of the bottom mount as it was difficult to get a spanner on. hth

[megadodo]

"Bolts used in structural areas should be of grade 8.8 or better. Such bolts will be marked 8.8 or 12.9 on the hexagonal head, however, cap-head bolts or 7/16" ( 11mm ) UNF seat belt anchorage bolts (with an anodised finish) not marked in this way may normally be considered to be of equivalent strength. Bolts should be M8 or larger."

 

Above is straight out of the manual, M8 is fine for bolts unless they are not maked *.8 on the heads in which case they must M11 or 7/16

[Guest smartfazer]

Does that mean I have just dismantled my lower anchorage points and hacksawed/ground off the high tensile ( 8.8 ) captive M10 nuts for no reason?

 

The version of the IVA manual that I have (Revision 3 dated: 29/06/2009) states as follows:-

 

NOTE 3: A suitable single bolt fixing of adequate strength would be, for exampple, a bolt of at least 11mm (7/16) diameter of grade 8.8. Other bolt fixings may be acceptable providing they are of equivalent strength.

 

NOTE 4: In order that a seat belt can be separated from the anchorage without causing damage to the anchorage, for example a mounting in the side of a tube or box section, it is a requirement that the bolt is secured into a "fixed" threaded hole or captive nut. (The presenter may be required to demonstrate this condition is met). The bolt may be secured into an alternative fixing, e.g. a lock nut of suitable strength, where access is provided to the "rear" of the mounting to enable separation/re-attachment of the belt.

 

 

 

I wish I had written this out before as I have just realised the answer to my own questions:- 1) Bolts must be at least 11mm (7/16) and grade 8.8 or higher. 2) Nuts must be captive unless you can gain access to them.

 

At least I can console myself that the original nuts/bolts I used were only 10mm.

 

Steve

[megadodo]

You have an old revison of the IVA manual, the latest version is dated June this year and is where I got the M8 bolt quote from! I think there is a link from this part of the forum somewhere to it, if not PM your email address and I'll send you the whole manual or you can download it from the VOSA website. But yes, you did remove all those bits unnecessarily, sorry!

[agent_zed]

i used 8.8 m10's for the top mounts and 11mm unf without markings on the heads on the lower mounts, as i happened to have the proper seatbelt ones so thought may as well use them. passed without issue.

[Guest smartfazer]

Thanks all.

 

 

Megadodo, where is the link to the version you mention? All I can get to is revision 4 dated 05/10, and nowhere does it mention M8 bolts being acceptable. But bolts must be minimum of 11mm (7/16) and 8.8 or greater

 

Steve

[steve in stockport]

section 19, seat belt anchorages states:

 

All Vehicles

What to look for:



Evidence that anchorages in a vehicle of the same, or a very similar type have been subjected to a seatbelt anchorage strength test to “European Standards” by a recognised authority. This may be acceptable where there is clear evidence that the structure is identical to the vehicle originally tested.



Welding should appear neat and of good quality; whilst it is impossible to judge the quality of a weld just by looking at it, messy welding is rarely strong welding.



Bolts used in structural areas should be of grade 8.8 or better. Such bolts will be marked 8.8 or 12.9 on the hexagonal head, however, cap-head bolts or 7/16" ( 11mm ) UNF seat belt anchorage bolts (with an anodised finish) not marked in this way may normally be considered to be of equivalent strength. Bolts should be M8 or larger.



Threaded bushes should be welded (at both ends) through the tube, and not end mounted on the surface. (A threaded bush may be attached by its side surface to a structural component).

[Guest smartfazer]

section 19, seat belt anchorages states:

 

All Vehicles

What to look for:



Evidence that anchorages in a vehicle of the same, or a very similar type have been subjected to a seatbelt anchorage strength test to “European Standards” by a recognised authority. This may be acceptable where there is clear evidence that the structure is identical to the vehicle originally tested.



Welding should appear neat and of good quality; whilst it is impossible to judge the quality of a weld just by looking at it, messy welding is rarely strong welding.



Bolts used in structural areas should be of grade 8.8 or better. Such bolts will be marked 8.8 or 12.9 on the hexagonal head, however, cap-head bolts or 7/16" ( 11mm ) UNF seat belt anchorage bolts (with an anodised finish) not marked in this way may normally be considered to be of equivalent strength. Bolts should be M8 or larger.



Threaded bushes should be welded (at both ends) through the tube, and not end mounted on the surface. (A threaded bush may be attached by its side surface to a structural component).

 

 

So, if I get this right, section 19 Seat Belt Anchorages contradicts section 31 Seat Belts.

 

I think Section 19 deals with the attachment of the fixing point and Section 31 deals with the attachment of the Seat Belt to the Seat Belt Anchorage...........Confused

[megadodo]

I believe that the reference to the 11mm minimum is where the bolt has NO grade marking (common on bolts supplied with belts (well, mine don't have them anyway!)but the wording in that section is poor. I'm sure no examiner would question 8.8 grade marked M10 bolts!