Category: GBS Zero

Both rear corners now assembled, but not yet torqued up. After reading through the Sierra Haynes manual I am not fully clear of what to torque to what. As this is quite important for my own safety I have send a email to Richard@GBS for clarification.

I had half an hour one evening this week, so I thought I would mock up some dash configurations. I have no intention of finalising the design until the scuttle is in place (many weeks yet), but I wanted my sub-conscious to work on this in the background.
Cut out some dial and switch sized pieces of card and arranged them on the GRP dash.

Found a forum thread will many many examples: locostbuilders

Continued building the off-side rear. Nothing torqued up yet but more to familiarise myself with how things go together using my reference photos from GBS as a guide as needed.
The chassis mounting brackets for the GAZ shocks required the holes cleaning before the bolts would fit through. Very tight fit. With the hub bracket in roughly the right position I then pushed the drive shaft into the diff, only to find that I needed to put the calliper bracket on first. The disks need to go on next followed by the calliper itself. The supplied calliper bolts look too long. If tightened I think they would actually touch the pads. I will need to shorten them by 8mm or so when I come to final fit.
Connected up the braided brake lines (long ones) and the hand brake cable so I can see the cable routings.
All looks OK so I will start on the nearside.

Having installed both rear drive shafts, I can understand why they can (almost) independently rotate. This is the main purpose of the differential and allows one wheel to move at a different speed to the other so you can go around corners. What I didn’t expect was that turning the prop shaft did not turn the drive shafts. It rotated freely and seemingly had no effect on the drive shafts. I was expecting some sort of direct linkage.
Is this normal, or do I have a problem with the diff?
I posted this query to the Rhocar forum and in return received this very interesting thread.

Rhocar link. There is a great U-tube link to a video showing how a Diff works – fascinating.

It turned out to be a school boy error in the end. The near side draft shaft was not fully located in the diff.

Continued with the off-side rear this afternoon. Another 14 nylon bushes and 7 crush tubes. Again I found this quite satisfying work and hanging the rear suspension feels like real progress

I have a query regarding the diff breather which I have posted to the Rhocar site.
I notice from other blogs that some diffs have a small tube leading from the diff to which a longer nylon tube can be attached. 

My diff doesn’t seem to have one. Is this a problem?


A very swift answer received from the wealth of knowledge which is the Rhocar forum.
RhoCar Thread


There should be a small pipe attached to the top of this plug that must have been broken in transit. GBS make a replacement.

Just seen a note from RichardL on my previous post regarding pedal box position.
His problem is the alignment of the hole pre-cut in the pedal box for the accelerator pivot and it’s alignment with the hole in the chassis for the other end of the pivot.
Mine looks very similar:
From the top the alignment looks OK. From the front you can see that the hole is 3mm-5mm too high


As none of these panels are fixed yet, below are some shots of the positioning of the pedal box so you can see how I have positioned it against the other chassis components.


Looking from the front I also have a concern about the positioning of the clutch cable aperture in respect to the cable mounting bracket. The pedal box hole looks too far right.

 Although time consuming I found this a quite satisfying activity (strange I know).

1. Clean powder coat from wishbone tubes
2. Copper grease the bush
3. Start the insert with a large M10 bolt and washers
4. Finish in the vice
5. Grind crush tube to the total width of the wishbone plus 2 inserted bushes
6. Copper grease the crush tube and push in with trusty M10

First two wishbones in place – at least temporarily as they will need to be removed to fit the side panels.
Tried to fit the upper ball joint but found sever resistance after only a couple of turns. I suspect it is powder coating in the threads. But I haven’t got a tap of this size so will have to source one.

I have left the final tightening of the nylocs to another day. Once the steering rack is in it’s final position and the connecting rod secured, I am sure the position of the steering column will need adjusting. After reading the long thread on the RHoCar forum about reuse of nylocs, I though this a pragmatic approach.

Tried test fitting the firewall and pedal box and encountered a frustrating problem that I know others have also encountered. In an attempt to keep the curve radius of the brake pipes as large as possible on exit from the master cylinder, the brake pipes stick out too far for the pedal box to fit around them. Unfortunately this means re-bending all of the brakes pipes throughout their full extent. Not easy when they are already bent, and not leading to a very neat final job as the pipes now have endless bends in them. This is one of those occasions when an information sheet would be very useful GBS.
Anyway, the pipes are now all re-fitted with additional clear plastic sheathing to prevent chaffing when they get close to chassis and panel corners or indeed each other as with the initial route under the steering shaft bracket.
I decided to route the fuel pipes along the drivers side of the central tunnel and the brake pipe and loom along the passenger side. The tricky bit is the route through into the rear of the car between the chassis and diff and ensuring clearance for the hand-brake cables to move unobstructed.

In the process of drilling my first rivet hole for a P-clip, I discovered that stopping the drill from wondering as I tried the pierce the chassis at an angle is very difficult even with sharp cobalt drill bits. So I made a clamp with a guide hole that I clamped onto the chassis for each hole. Made the process a great deal more predictable and much neater.
Once the nylon fuel pipes were pinned in situ, I connected them to the swirl pot in the front and low pressure pump at the back. I found a problem here with the supplied jubilee clamps. On the small diameter hose these clamps tend to distort and then the screw tends to miss the thread and fail to tighten any further. I think I will source some more and replace them. I really don’t want  fuel leaks and especially ones that will potentially only become visible once the car is almost complete. Replacing them then will be much more difficult.
Finally I connected the hand brake switch terminals and brake switch terminals to the loom, as well as replacing the existing terminals for the low pressure fuel pump for the supplied spades and terminal block.

Took a trip to GBS this morning. I dropped my wife at McCarthur Glenn Retail Outlet on the way past, so my time at GBS needed to be brief to avoid serious credit card damage.
There were a number of items missing when I collected the kit:

• Tyres – they had been “borrowed” for the track day
• Brake reservoir and cap – having supply issues
• Catalyst – although Richard@GBS  explained that he is developing a new exhaust with built in Cat which can be re-packed (I will probably swap for this when it’s ready)
• Steering column surround
• Anti freeze

 I did manage a couple of other jobs. Completed the placement of the swirl pot and high pressure fuel pump. Gave the steering column a coat of hammerite.

My immediate aim is to finalise the cable and pipe routings through the central tunnel before I start to box this in with side panels.
I have made a reasonable guess at a brake pipe routing so the next pipes are the fuel pipes. To get a fixed datum for the fuel pipes I have decided to start at the back with the low pressure fuel pump and fuel filter. These are mounted on a GBS supplied mounting plate which has pre-drilled holes for the chassis mounting points, the filter bracket and the rubber fuel pump mountings. Positioning the mounting plate and marking the position for the rivnuts on the chassis was straight forward. Drilling the chassis mounting points to 9mm for the rivnuts was a little tricky as it is difficult to get the drill in the right position to drill squarely. But with a little perseverance…..
Mounting the low pressure fuel pump and filter was straight forward although I did choose to add a piece of plastic between the collar and the filter to improve grip, taking care to make sure that the jubilee clip is accessible from above (the eventual boot).
Next I mounted the high pressure fuel pump on the drivers bulk head and riveted the mounting bracket for the  swirl pot onto the chassis. As with the low pressure fuel pump mounting bracket it is difficult to get a good angle for drilling the rivet holes for the swirl pot mounting bracket. Unfortunately GBS supplied small self-tapers in the swirl pot fixing kit instead of 20mm M6 bolts for the rivnuts. As I will be heading up to GBS tomorrow I will pick some up there then and complete the installation.

Before I head up to Newark tomorrow I wanted to get a good feel for the routing of the pipes and cables so that I know what to look for. So I threaded the fuel pipes and loom through the central tunnel to get the feel of it. The problem area seems to be above the handbrake Y adaptor and through into the rear compartment. There is not a lot of room and a great risk of the cables/pipes chaffing against the moving parts of the handbrake. I will have a very close look at this at GBS tomorrow.

Just got back from Lanzarote: 30 degrees plus each day, clear blue skies and a nice breeze. Landed at Birmingham: 16 degrees, grey skies and rain. Great to be back.
… but whilst it’s raining there is always work to be done in the garage 🙂


Spent a few hours today, drilling, de-burring and riveting the foot well panels for both drivers and passenger sides as well as the rear panel. 


Cleaned down each panel and frame with white spirit after de-burring, before laying a bead of “black glue” along the chassis to cover each hole. Once riveted, I also added a bead of “black glue” around the inner seam to ensure the panels are a water-tight as can be. Where the panels don’t fit snuggly around the chassis, then I filled the gap with “black glue” also. If this looks ugly when dry I will remove it and try something else. 

I only riveted the flat chassis rails on the back panel and have chosen to simply use the “black glue” for the circular rails. I only riveted the central portion of the left and right edges of the back panel. The reason being that drilling into the corners without a right-angle drill attachment is pretty much impossible, and with all of the other rivets and cement, these extra rivets will not add anything substantial to the stiffness of the rear end.

The chassis welding protrudes slightly in some places so a little bit of filing was required to get a good square fit for these panels. 


I marked the chassis position worked out the even spacing of the rivits the drilled and deburred the panels. After clamping in place I drilled the first hole into the chassis and popped a Cleco in. Then went around the rest of the panel.


Both panels are now fully drilled and in situ, but I still need to debur the chassis holes, get the black glue out and then rivet. 

Before I fix any of the panels I want to know where the brake lines are going. I have researched the recent blogs and have some photos from a factory build at GBS. Unfortunately the factory build was a left had drive and I had forgotten this. That confused me for a while. 
I decided to star at the master cylinder with the single rear pipe first. Down and under the steering shaft mounting. Over the chassis member and along the driver side tunnel. Under the handbrake mounting and then between the two handbrake cables and under to the splitter.
Next the offside (drivers side) front. Down and under the steering shaft mounting as with the rear. Over the chassis member and the around the front of the drivers footwell panels, leading the pipe straight above the steering shaft and then along the under side of the upper outer chassis member.
Then the nearside front. Down and under the steering shaft mounting as with the rear and the offside. Over the chassis member and straight along the cross member. Then around the front of the passengers footwell panels, leading the pipe straight above the steering shaft and then along the under side of the upper outer chassis member.
This exercise made it obvious that the drivers and passengers footwell panels need to be fixed before much longer as the the routing of the fuel lines is only possible once the swirl pot is in place and the panels need to be fixed before that.

Decided to make a start on the brake pipes. The rear fix as they seemed the least complex. Attached the 4 way splitter with a bolt rather than the rivnut. The hole in the chassis is too big for the rivnut. They connected the brake light switch to the splitter.  

 I started by bending the brake pipes without connecting to the splitter or the flexible braid which I had temporarily fixed to the chassis. This gave me the freedom to bend the pipes in my hands away from the chassis. But, when I came to screw the connectors into the splitter and flexible hose it changed the pipe length once the nuts were tightened. So second attempt was to anchor one end of the pipe (screwed into the splitter) and bend the pipe whilst attached. Much harder, but eventually allowed me to reach the braider connector via a suitable anchor point for a P clip. Courtesy of the local B&Q shop I also added some clear plastic pipe to avoid chaffing as the pipe bent around the chassis at each side.
One thing I couldn’t figure out was which braided hoses went on the front and which on the rear (small or large). Without the suspension and brakes attached it was 50:50. I must remember to ask.

I still had a little time left, so I looked for another small job that would get me closer to being able to complete the wiring and pipe runs before boxing in with panels.
The handbrake assembly seemed a good bet. This needs to be in place in order to route the fuel and brake lines through the tunnel without risk of snagging against the moving parts of the handbrake.

Not a difficult job at all – just a few minutes to position and bolt the lever down, assemble the link cable and brake cables and attached them all together. I chose to use the lower of the attachment points on the base of the handbrake lever for the link bar. Simply because the cable seemed to snag if I used the upper one.

Now the basic clutch/brake pedals are in place, I think its time to fix the master cylinder and push rod for the brakes. I was looking for a short job and this was just perfect – about an hour or so.
Started off reading the Kitspares guidance, and also other blogs. There seems to be a tendency to cut the push rod bold too short which will either leave not enough travel on the brake pedal or not enough in the cylinder itself. The final length of the rod will be determined by where you want the brake pedal to rest (idle) and the throw of the pedal once the brakes are bled. As I can’t determine either at this point I have opted for the safe option – just cut the head off the bolt i.e. push rod at maximum length – for now.
Next job the link pin connecting the pedal to the fork end and push rod. As you can see from the picture the pin is 8mm and the pre-drilled hole in the pedal is not. I don’t think this is a design floor on the part of GBS, rather an efficiency measure. This allows them to make one pedal for both the clutch and the brake.
After drilling the 8mm hole for the pin and filing down the push rod end to fit the master cylinder, it all went together cleanly. I tightened the master cylinder securing bolts just enough to hold in in place and then pressed down on the brake pedal a few times to exercise the push rod inside the cylinder. This moved the position of the master cylinder slightly such that the push rod went in centrally and straight. I then tightened up the master cylinder securing bolts. Job done.

I am not happy with the pedal position at rest – it looks far too high, but I am not going to adjust it until the brakes are bled. There is adjustment on the thread of the push rod or I can simply cut a bit off

The fitting of the brake and clutch pedals id covered by one of the few information downloads from the Kitspares download area. The theory is not complicated: locate the plastic bushes into the pedals and the chassis, and add a pivot bar and spacer. In practise, what can seem like a simple job actually tasks a few hours to perform.
I order to locate the plastic bushes in the pedals, you first need to clean the powder coat from the inside of the pedal casings. A barrel sander and some manual emery sanding did the job. Then you need to ease the plastic bushes into the casing with the aid of copper grease (or alternative lubricant) making sure that they go in square. After trying a G-Clamp I eventually opted for a my vice to do this.
For the chassis bushes, I obviously couldn’t use the vice so I used a nut and bold and some penny washers. This was not as easy as the vice but slowly and carefully I eventually eased the two bushes into place.
The real issue with this piece of the build was the steel rod that acts as the pivot for the pedals. This is slightly too big in diameter for easy assembly of the pedals and movement of the pedals once assembled. Unless you have a lathe, it’s pity much an hour or so with emery paper rubbing away a few thousandth of an inch to get a better fit. I have left the fitting quite tight as I expect the joints to get easier over time. 

Looking at the clearance between the pedals and the steering shaft, I think it looks OK. 


Murray has just lost the Wimbledon single s final. 🙁


My youngest daughter had a laptop for her birthday recently, so I re-built her old desktop for use in the garage. I have been using it to follow blogs, but it’s also capable of watching Andy Murray this afternoon whilst I was reducing the pedal bar with emery paper.

Whilst the powder coat should keep the rot at bay, it doesn’t help with screw threads -but nothing a 7/16th tap couldn’t deal with. Plenty of WD40 as lubricant. Half turn forward and quarter back. 
All 8 mounting points cleaned up.  Tried the seat belt mounting bolts in the clean threads to make sure.