Installing an RAC Roll Bar

I took some convincing that it was necessary to replace the standard Westfield supplied roll bar as I had assumed that the factory would not supply a safety feature that was purely cosmetic but having had it pointed out to me that my head was above the roll bar’s top, I had to conclude that in an accident resulting in the car overturning, my head would not be adequately protected.

In a way, this is part one of the whole procedure as ultimately, the boot box will have to be modified or a replacement made, to accommodate the rear struts of the RAC roll bar as it will be seen during assembly that these struts will pass right down the side of the boot box and through the floor of the box. The boot box can be modified to suit but to do the job properly and neatly will require a lot of careful planning and for various reasons I decided to carry out this work at a later date and instead, to make a cover for the boot box aperture for use until time allows. Having said that, the resulting cover is both practical and attractive!

The following parts should be supplied by Westfield

1 x Roll Bar with diagonal bracing welded in
2 x Rear Struts
4 x Rose Joints
4 x Reducers for the Rose Joints
4 x Retaining Nuts for the Rose Joints
2 x 50mm x 10mm Bolts (top mount)
2 x 60mm x 10mm Bolts (bottom mount)
4 x 10mm Lock Nuts for above bolts
4 x 10mm Spacers for bottom mount
6 x 10mm Cap Head Bolts
6 x 10mm Lock Nuts for Cap Head Bolts
26 x 10mm Chamfered Washers
4 x Plastic Nut/Bolt Covers

The Kit of Parts as it should be supplied

Removal of the Standard Roll Bar

If wet weather gear is installed, the ‘pram’ roof structure needs to be removed first by unbolting the two 5mm bolts on each vertical bracket.

Next, the boot box must be removed and if race harnesses are in use, the eye bolts that retain these at the top must be removed to allow the boot box to be lifted out. If these have been fitted correctly in the first place, they will be tight and have their ring edges facing in the direction of ‘pull’ of the strap. To achieve this originally, it may have been necessary to use extra washers as well as any spacers required for the harnesses to pass the SVA requirements for mounting height. To ensure that the eye bolts return to the correct orientation when re-fitted, it is recommended that they are stored on a piece of cardboard with cross cuts made in it suitably labelled to identify which bolt came from which mounting tube.

The Harness Eye Bolts in careful storage

Once the boot box is removed, access will be gained to the underneath of the roll bar mounting plinth and the two roll bar retaining bolts can be removed using a 19mm socket. With the two bolts removed, the old roll bar can be lifted off, exposing the two glass fibre ‘tongues’ that retain the top of the body tub to the chassis. These tongues should be cleaned off with either white spirit or methylated spirit and then covered in strips of masking tape. It is also recommend that you mask off the top of the body all round the boot box area to protect it.

With the tongues suitably masked, the RAC roll bar can now be placed on top and marks made through the three mounting holes on both of the bases to give a guide to the location of the three pre-cut mounting holes in the chassis. The RAC roll bar can then be removed and the test pilot holes made through the glass fibre tongues to locate the exact position of the pre-cut holes. The holes in the glass fibre can then be filed out to match those in the chassis and the RAC roll bar placed back on the top of the tongues. Trial fit the six Cap Head Bolts and if all is well, remove the Roll Bar again.

Fabricating the Boot Box Aperture Cover

With no boot box, you now have a large aperture in the rear of the car that needs to be filled and assuming for now that you do not intend to modify the boot box to accommodate the rear struts, then a cover plate will be required. I used a sheet of approximately 1.5mm aluminium for this purpose and by placing the boot box upside down on top of the sheet and drawing round the perimeter with a felt tip pen, a good approximation of the required shape can be transferred onto the sheet. After removing the boot box ‘template’, immediately mark the sheet with the word ‘bottom’ so that there is no confusion later!!

Trial fit the cover onto the inner lip of the boot aperture and cut and file accordingly until you get a good fit around the perimeter. Also make half moon cuts for the inertia reel ‘turrets’ (if applicable) and 25mm holes for the harness eye bolts (if applicable). Using masking tape on the sheet, mark suitable datum points to indicate the correct location of the sheet in the aperture to ensure repeatability of fit each time you remove the sheet for fine filing etc.

Trial Fitting of the Cover

When you have got a good fit in the lip of the boot aperture and around the other item mentioned, ensuring that all the datum points match up, drill at least nine 5mm holes at a distance of 12mm from the edge of the sheet cover in strategic positions around the periphery to fasten the cover to the body. Using these holes as a template, mark through the sheet and onto the lip to give the position of the matching holes in glass fibre. Remove the sheet and drill 7mm (or maybe 7.5mm depending on your make of Rivnut) holes in the glass fibre lip to accommodate 5mm Rivnuts. Carefully sand the underside of each hole to remove burs and loose glass fibre and then insert and pull the Rivnuts.

Drill out the holes in the aluminium sheet to 5.5mm and trial fit the cover to the boot aperture and fasten it down loosely with 20mm x 5mm Allen Head Stainless Steel bolts, ensuring that all the datum points match up. Assuming that all is well, remove the sheet.

Using the six supplied 10mm cap head bolts, washers and lock nuts, the roll bar can be secured to the chassis using a 17mm socket and an 8mm Allen key wrench. All but one of the cap head bolts are inserted from the top but it is important to note that even if you are able to fit the cap head bolt that goes in the near side front location (under the diagonal strengthening bar) you will not be able to get an Allen key wrench onto to it so it will have to be inserted from underneath with the nut at the top. You could of course insert them all upside down but they look better with the cap head at the top. The order of installation is bolt, washer, roll bar base, glass fibre tongue, chassis, washer, lock nut. I used a smear of ‘copper-slip’ on all the threads.

Now place a ‘straight edge’ or tight piece of string (held in place with masking tape) on the rear of each of the bases and mark a new datum point on the masking tape on the top of the body side to indicate the position of the roll bar. Next do the same with inside edges of the each base placing a datum mark on the front and rear of the aperture. These datum marks describe the position of the Roll Bar bases and indicate the rectangles that need to be cut out of the front corners of the boot box aperture cover. Remove the Roll Bar and install the cover again with some of the 5mm bolts ensuring that all the datum points match up.

Using the new datum marks, join up the marks and produce two rectangles describing the Roll Bar bases on the sheet. Remove the sheet and cut out the two rectangles.

The Cover with all sections cut out

Detail of offside front corner

Re-fit the Roll Bar, aligning its edges with the new datum marks. Fully tighten up all six bolts.

Nearside Roll Bar Base

Looking down into the rear of the chassis, you will see the mounting bracket for the bottom of the two rear struts on the sloping chassis members either side of the fuel tank. The bolt holes in these will need to be gently reamed out with sand paper rolled into the shape of a tube to remove the excess powder coat to allow the 60mm x 10mm bolts to pass through.

The bottom mountings for the rear struts can now be installed in the following order starting from the outside moving in towards the fuel tank side:- bolt, washer, bracket, spacer, rose joint (with reducer inserted and locking nut on the protruding thread!), spacer, washer, bracket, washer, lock-nut. This lot can be tightened up firmly. Again, I used copper-slip on the thread.

Bottom Rose Joint in place on chassis

Fitting the Rear Struts

The rear struts can now be trial fitted by carefully holding the thread of the Rose Joint (now installed on the bottom bracket) and screwing the rear strut onto it. It will become clear that the strut cannot be located onto the top mounting on the Roll Bar as it is touching the side lip of the boot box aperture! With the lip suitably masked off, you will need to file a smooth curve into the lip to accommodate the strut BUT you will also need this to sweep back to allow the strut to slide forwards and into the cut-out to allow the top Rose Joint to slide into the top bracket! The shape of this sweeping curve will vary greatly between installations (the two I did over the Easter weekend were entirely different) but the diagram below is an indication of the required shape.

Once the rear strut can be slid into position, the top rose joint and its locking nut can be screwed into the top of the strut and the thread screwed in or out to make the ‘eye’ of the Rose Joint match up with the top bracket. The top bracket too will need to be reamed out with a roll of sand paper to remove the excess powder coat thus allowing the 50mm x 10mm bolt to be correctly inserted. The top mountings for the rear struts can now be installed in the following order starting from the outside moving in towards the centre of the car:- bolt, washer, bracket, washer, rose joint (with reducer inserted), washer, bracket, washer, lock-nut. Do not tighten this up yet, trust me, it is going to be removed several times before you need to consider tightening it! You can, however, tighten the top locking nut on the Rose Joint as this sets the total length of each rear strut.

Top Rose Joint in place on Roll Bar

Stretch a piece of string (held in place with masking tape) across the boot box aperture so that it just touches the front of the two rear struts whilst pressing the string down onto the boot box aperture lip and mark a datum point on the masking tape. Repeat this for the rear of each strut. Then, using a straight edge touching the outside edge of the roll bar and a strut, mark a line on the front and back of the lip of the aperture. Do the same for a straight edge line touching the inside edges as well and then repeat for the other strut.

String used to find Strut position plus datum mark

Remove the top retaining bolts and unscrew the struts from their bottom rose joints and using masking tape, label them respectively left and right hand struts. Now wrap a piece of paper tightly around the top half of both struts and secure with Cellotape to protect them during the next phase and place them to one side for now.

Place the cover back in the boot box aperture and affix with some of the 5mm bolts ensuring that all the datum points match up. Place a reasonable area of masking tape on the cover in the approximate position of where the two struts will pass through and using the datum marks obtained with the string and straight edge earlier, draw in the two rectangles that describe the position that the struts will pass through by use of the string and straight edge again.

Rectangle describing Strut position on cover

Using graphics software or by hand if necessary, draw an ellipse that touches all four sides of a rectangle 2mm larger in both width and length as that produced on the cover.

Cut out the ellipse to use as a template and transfer this to the two rectangles on the cover. Remove the cover and using a 3.5mm drill, drill numerous holes just inside the ellipse then cut or file between the holes to produce a nice clean smooth finished pair of ellipses.

Ellipse drilled out ready for finishing

The rear struts can now be trial fitted again by carefully holding the thread of the Rose Joint and screwing the rear strut onto it. Now, carefully slide the cover over the two struts (now you see why you have wrapped the struts tightly with paper!!!) and by careful fiddling position the cover and struts in their final position. Once everything is correctly lined up, there should be an even gap in the ellipse all around the struts. If the fit is not perfect, remove the covers and file accordingly.

Once all is well, sand all the edges to give a really smooth finish ready for the final embellishment which can be paint, polish or foam and vinyl which is what we used on ours.

Cover covered in foam ready for vinyl

When the final finishing is completed, assemble the rear struts and cover again and fit the 20mm x 5mm stainless steel Allen head retaining bolts (with washers) to retain the cover in place. Finally, re-fit the eye bolts for your harness if you have one. I had extra long eye bolts whereas Simon's were a good bit shorter and it was necessary for me to shorten one of my bolts (the nearside one on my four point harness system) to allow it to slide under the diagonal cross member of the roll bar. You may not need to do this if you are lucky but if you do need to do it, do it properly! The most common method of shortening a bolt is to screw a nut onto it past the area to be cut off, cut off the unwanted portion and then 'clean' the thread by un-screwing the nut - DO NOT DO THIS! The correct method (IMHO) is to cut the thread off at an angle matching the thread and then to file away any sharp edges VERY CAREFULLY with a very small flat file being sure that you do not slip and hit any of the rest of the threads. Then, carefully 'dress' the thread end to ensure that it is well formed (don't be afraid to use a magnifying glass to be certain!). Close examination and 'touch' will tell you when the job is completed and a trial fit into a nut (NOT the mounting tube on the chassis) will confirm whether you have done the job properly or not. This bolt is a vital safety feature and you do not want to take any risk of scoring the thread of the mounting tube with a badly formed thread end!

The finishing touch is to clip on the plastic covers supplied in the kit to the top mountings. However, looking at the photograph below you will also see what appear to be two black washers either side of the rose joint - these are in fact cable ties. These have been installed to stop the whole strut brace from twisting by virtue of the fact that it is mounted top and bottom on nice easy to rotate rose joints!

Cable ties and plastic covers installed

Finished Installation on my car

Finished Installation on Simon's car

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