Triumph Herald or Spitfire steering rack in a Lotus Seven Series 2/3
My left hand drive 1969 Lotus Seven Series 3, fully constructed by Lotus and shipped to Canada – like all the Series 2 and 3 cars, was fitted with a modified Triumph Herald steering rack. A previous owner (I’m the third), raced and slalomed the car, and the frame and steering suffered damage due to this. I decided to check the steering rack after the car suffered further damage. The driver’s side tie rod was badly bent at the ball end. On strip-down it was noted that the rack was very slightly bent at the same end causing excessive rubbing on the rack housing.
My Herald rack differed very slightly from that fitted to the Spitfire. The Spitfire rack has a heavy gauge almost circular retaining bracket (called an abutment plate), fusion welded on the ‘passenger’ end just in from the rack bearing. This bracket holds the rack firmly between the rack mounts on a Triumph Spitfire (or Seven), and prevents side to side movement of the rack in the chassis. Due to the welding process, the area where the bracket is located can shrink slightly more than the original diameter. This may complicate removal of the rack end bush (details below).
The Herald and Spitfire rack may have one or two holes drilled in the top of the rack tube as it sits correctly oriented in the rack mounts. Nylon ‘plugs’ fit in these holes and also fit in depressions in the rack mount caps. An on-line site noted that as well as correctly locating the rack tube in the mounts, they act as a ‘damper’ of sorts on the geared rack preventing excessive ‘slop’. Wear may cause the length of these plugs to vary in length.
Both my original outer (steering) ball joint, and the track rods – where they screw in to the outer ball joint – had been shortened by Lotus to provide the correct tracking. Thankfully, although no longer serviceable, I still have these parts for future comparison.
A helpful web site www.super7.dk provides information from Lotus regarding the rack and pinion assembly. The site also details other modifications and suggestions to replace components that may no longer be available. The web site owner of SB 1215 (I cannot find his name unfortunately to thank him), wrote:
“Rack & Pinion Assembly“
From the Lotus Seven – Master Parts List (1964) I have the following information:
This rack and pinion assembly of Standard Triumph manufacture, is as fitted to the Triumph Herald with the two following modifications. Two lock limiting spacer tubes are fitted on to the rack to limit its movement, and 3/8” (9.5 mm) and 1/4” (6.4 mm) is cut from the mating ends of the tie rods and ball joint assemblies respectively to allow for toe-in adjustment.”
This web site also advises the following:
“The Herald/Spitfire tie rod is 8.715 inches (ball centre to thread end) but the thread cannot usually be altered because of the rolled threads”.
Another web site from the Triumph Sports Owners Association in Australia, provides a chart which includes tie rod length measurements for Standard Triumph vehicles that used the Alford and Alder rack. The lengths are measured from the end of the thread to the centre of the ball. For the GT6, Spitfire, Herald and TR4, the length is quoted as 170 mm or 6-11/16 inches.
I found an on-line site where a Triumph enthusiast has provided downloads of workshop manuals featuring many of the Standard Triumph models. In a Herald 1200/Spitfire/Vitesse manual the measurement for the outer ball joint centre to the tie rod ball centre is noted as 8.715 inches (221.36 mm). This is the same measurement provided by the owner of SB 1215, but it isn’t just the tie rod length, but the whole assembly of tie rod and outer ball joint for the Triumph vehicles mentioned above.
Dave Bean Engineering in their Lotus Elan, Plus 2 and Cortina catalogue quote the tie rod lengths for the Europa, Elan Plus 2 and Seven as 7 inches or approximately 178 mm. The Elan is noted as using a 6 inch tie rod. Both the Plus 2 and Europa required tie rod extensions. DBE does not indicate if the tie rod length is measured from the ball centre or from one end to the other.
I have measured the original undamaged tie rod from my Herald rack to be 6-5/8 inches measured from the centre of the ball to the very end of the threaded portion. These tie rods are sawn at the end (presumably by Lotus), and appear to conform to the specification noted in the Lotus Seven Master Parts List (1964), after 3/8 inches was removed from the end. The U.K. motor industry was still using Imperial measurement in the 1960s (the U.K. started the process of going part metric in 1965). I’m assuming that the Stanpart tie rods would be measured in inches for parts manufactured prior to this date (and probably after?), and would be produced to 7 inches long. Similarly the (outer) ball joint from my Seven shows saw marks on the end, and the ball joint measures 2-5/8 inches from the centre of the the ball to the rod end. British Parts North West advised me that the length of their replacement tie rod is 7.125 inches long from end to end, and the thread is 2 inches long.
New tie rods and ball joints can be purchased from various Triumph parts dealers, and at least one tie rod manufacturer beefs up the area between the ball and the rod more so than the original. Another site notes that the area next to the ball requires the taper in order to allow maximum movement of the tie rod in all directions. Unfortunately this is where ‘curbing’ or dropping into a pothole can bend this vulnerable section of the rod. If cutting the threaded end from a new tie rod for a Seven (or any Lotus or kit car), it is worth screwing on the (outer) ball joint lock nut first. When the end is sawn through, removing the lock nut will clean up the threaded portion of the sawn end.
As noted above, at each end of the rack – inside of the tie rod ball joints – there are rack spacers to limit lock-to-lock movement. The Triumph Herald/Spitfire/Vitesse/GT6 and possibly other Standard Triumph vehicles have very tight turning circles often compared to that of a London Taxi. For Lotus road cars, including the Elan, Elan Plus 2, Europa, and Seven (all using the Alford and Alder designed rack), they require rack stops to prevent the front wheels from rubbing on the bodywork causing damage. Rack stops are also considered a necessity on Triumph based racing cars, as the excessive lock to lock is sometimes a hazard.
Note: Alford and Alder were acquired by Standard Triumph in 1959. A Hemmings website provides the names of other manufacturers who used Alford and Alder components for steering and suspension requirements.
The rack stops on the four mentioned Lotus cars vary in length and type. Dave Bean in his catalogue of the Elan, Plus 2 and Cortina, illustrates the rack stops for the first two cars and also includes the Europa. The illustration looks as if it has been reproduced a few times but I may be able to supply a readable copy of the page if anyone is interested (postage cost only).
For the Lotus Seven (and early Caterham 7s) the rack stops are 1 inch long x 1 inch outside diameter. They are made of thick wall mild steel tubing and are reamed internally to be a slide fit on the rack. I measured my rack with an electronic calliper in various places, and on average it was 0.819 inches outside diameter. There may be very slight diameter differences compared to other racks, but once greased, the stops just have to slide easily on the rack.
Note: Lotus does not appear to have designed them to be a tight fit (on my rack at least). Binding or seizing in place on the rack could be extremely dangerous leading to loss of steering. These rack stops are indicated in the Lotus Seven manual on page I2 (i 2) as part number 7987 – item number 84, in the section dealing with front suspension and steering. However, they are not mentioned in the dismantling and reassembly of the rack for some unknown reason (details below).
A Youtube video that I watched involving a strip-down and rebuild of a rack, only showed replacement of the rubber gaiters (also called ‘bellows’). If considering a full strip-down, the following parts can be replaced with items still available from various Triumph parts dealers:
- Rubber ‘O’ ring that fits inside the pinion collar.
- The steel backed bronze bush for the ‘passenger’ end of the rack tube.
- The kit of rubber gaiters (different for right and left) with clips and wire or tie strap(s).
The originals may have gone soft or show signs of wear or tearing. One Triumph site recommends fitting a nylon disc between the end of the gaiters and the securing clip to prevent the clip from tearing the rubber in normal use.
At least one parts dealer I checked still had shims available in a couple of thicknesses for the tie rod ball joints and possibly the rack and pinion assemblies. I have made use of a small supply left over from my original rack that was not repairable.
In the Lotus Seven Owners Manual (mine published post August 1965), Lotus provide a detailed description of the removal, inspection, and assembly of the Herald rack and pinion steering mechanism. Caterham Car Sales also include this in their Series Two, Three and Four Owners Manual.
Lotus mentions ‘a pinion retaining nut’ in the paragraph on dismantling and then again in the assembly section. No mention is made of a circlip to hold the complete pinion shaft assembly with bushes, shim pack, collar, and thrust washers in the pinion housing. I have noted this circlip on three different Triumph racks, one on my original Herald rack, and two on Spitfire sourced racks. The manual refers to both a ‘cap nut’ and a ‘pinion retaining nut’. Lotus does provide measurements in thousandths of an inch to adjust the pinion float, cap nut to pinion housing clearance, and tie rod ball-in-cup lift (manual pages reprinted below). Referring back to an on-line video, a Lotus owner with the aid of a small punch, is shown driving out the lower pinion bush and steel cap. Unless the bush is badly scored or damaged where the lower hardened thrust washer slides against it, there really is no reason to drive the bush and steel cap out of the housing. If an insufficiently sized punch is used on the steel cap to drive out the lower bush (which is a force fit), it can distort the steel cap (from experience!). Then if planning to re-use the original shim pack without checking the end float, it may not provide the correct clearance when fitting all the original parts back in place.
An on-line Triumph site notes that the Standard Triumph Alford and Alder racks were designed to be lubricated with oil (similar to the trunnions), not grease. It notes that ‘modern fluid or self-levelling greases such as Castrol SL appear to be an acceptable alternative’.
On-line videos detailing a strip down of the rack and removal of the tie rods, show owners using large adjustable plumbers wrenches and/or crescent wrenches to remove the locking nut and cup nut. I have seen badly rounded parts using this method. I found a pair of 1-5/16 inches (SAE) chrome vanadium spanners/wrenches of very good quality and price ($19.99 Canadian each, made in China – naturally!). I purchased these from Princess Auto (Canada). They fit the cup and lock nut perfectly, causing no damage to either. They are quite long allowing good leverage for the job at hand.
I conducted a check on-line for steering rack servicing recommendations. A helpful Triumph forum provided information that new steering racks – as replacements for the Herald, Spitfire et al – are available manufactured in Germany to an equivalent standard of quality as the original Standard Triumph supplied units.
One forum contributor mentioned a U.S. Triumph parts supplier called British Parts North West. An agent at this company told me that BPNW had sent a German manufactured rack to Dave Bean Engineering in California for assessment and possible disassembly, to ascertain its suitability for use in Lotus cars. He suggested that I contact DBE for full details. A Dave Bean agent advised that the German made rack would not be suitable for Lotus vehicles as it was different from the Stanpart item, and could not be modified to suit their requirements.
I mentioned at the start of this topic that the Spitfire rack tube could shrink slightly due to the welding process used to install a rack mount abutment plate. When I inquired on one Triumph forum how best to replace the rack end bearing, one owner advised that he dropped a suitable sized socket down the rack tube in order to drive out the bearing at the ‘passenger’ end of the rack. I tried this method but the socket became jammed, and would not pass through the section where the rack abutment plate had been welded due to the slight shrinkage in this area. Using a smaller socket did not work and merely passed through the bearing as there is so little surface area on the end of the bearing to grip on to.
A solution I discovered was to use a thick flat washer (same o.d. as the bearing) with two opposite edges slightly removed that can be dropped easily down the tube clearing the obstruction. Using a 3/4 inch mild steel tube, the bearing can be carefully punched out without damaging the rack tube. Replacement of the bearing is best accomplished by using a hide or hard plastic body mallet to drive the new bearing back in place.
Another possible solution may be to use a tool that is used to remove the clutch pilot bushing from the end of a crankshaft. I have seen them advertised in the U.S. by a company called ‘Harbour Freight’. They consist of a small puller with two or sometimes 3 sprung ‘claws’ attached to a slide hammer. The claws grip the inside end of the bearing, and using the slide hammer, ease the bearing out of the crankshaft, or in this case, the end of the rack tube. Please note that if the bearing is showing no signs of wear and the rack is not a sloppy fit when slid inside the bearing, replacement may not be necessary.
Lotus advise: “Examine the bushes in the end of the rack tube for wear and damage. If necessary renew them, pressing the new bushes into the tube, the first with the innermost edge of the bush 1.75 in. (44 – 45 mm) in, the second with the nearest edge of the bush flush with the end face of the tube”.
My original Herald rack tube as well as a Spitfire rack that I own, only have one steel backed bronze bush 1.5 inches long. The bearing number is Stanpart 128002. The machining in the end of the rack tube is also only 1.5” inches deep to take the bearing. I cannot find any information indicating that early 1960s Herald racks were constructed differently from later 1960s units. My Stanpart Triumph Spitfire Spare Parts Catalogue 5th edition (no printing date mentioned), and covering the Mk. I and Mk. II Spitfire only, confirms the one bearing as part no. 128002.
A member of the Lotus Seven Club U.K. inquired on their forum regarding a small dowel pin fitted in the alloy pinion housing. This dowel prevents the steel retaining ring from turning with the pinion and causing wear in the alloy housing. The ring and alloy housing each have semi circular grooves machined in them to hold the dowel. If the original dowel is missing, the non-drilling end of a broken or dull 5/32 inch drill bit can be used. Using a Dremel tool or similar to cut off the hardened drill bit end, ensure that the piece of cut drill bit is not too long thus preventing the circlip from safely fitting into the machined groove. Alternatively I found a large pop rivet nail that also fitted exactly, cut down to the correct length.
One forum member advised that after removing the circlip (which holds the pinion assembly in place), plus the cap nut, shims, spring and plunger from the top of the rack, he was unable to remove the pinion assembly. I disassembled a Spitfire rack some time ago and encountered the same problem. After cleaning out the circlip groove, and degreasing the assembly as much as possible, the pinion still would not budge. I tried using a slide hammer on the pinion using as little force as possible just to jog it loose, but it would not slide out. Using a propane torch, I very carefully heated the alloy housing near the circlip groove, and the pinion assembly withdrew very easily. Examining the retaining ring and upper pinion bush, I noted pitting on the outside of both that had made them difficult to remove from the alloy housing. I am not sure if this was caused by galvanic corrosion (the assembly was heavily greased before I stripped it down), but it really complicated removal of the parts.
Just a tip: My local friendly dentist, who is also a sports car fan, gave me some free, disinfected, well-used dental tools that are ideal for removing small oil seals (such as in the retaining ring) without damaging the parts they are attached to.
Specifications from a Stanpart Workshop Manual for the Spitfire steering assembly.
Pinion end float should not exceed 0.010 inches (0.254 mm)
The clearance for the rack plunger should be 0.004 to 0.008 inches (0.1016 to 0.2032 mm)
Tie Rod end float within 0.0005 to 0.003 inches (0.0127 to 0.0762 mm)
Steering safety clamp:
Clamp bolts 6 to 9 lbf/ft. (0.8 to 1.2 kgf/m
Grubscrew 18 to 20 lbf/ft. (2.5 to 2.8 kgf/m)
I have included the torque readings for the adjustable steering column safety clamp as I will fit this unit to my car. My car originally had the one piece column, but a previous owner had cut and shortened it, then had it welded back together. It didn’t look very safe, so I purchased the two piece column, and It can be adjusted for the best fit.
My appreciation to the following:
- Terry O’Beirne at www.macleansbridge.com with the Triumph Sports Owners Association
- vitessesteve.co.uk Downloads of Standard Triumph Workshop Manuals.
- The Owner of SB 1215 at www.super7.dk
- Dave Bean Engineering
- Triumph Experience Forum
- British Parts North West
- Rimmer Brothers U.K.
- Simple Sevens and John Donohoe
- Historic Lotus Register. Back issues available. A great Lotus Seven edition – number 90.
- Golden Gate Lotus Club www.gglotus.org. There is a complete copy of the 1964 Lotus Seven Master Parts List available on their web site for download.
- Lotus Seven Club forum. Great advice, but this club now mostly consists of Caterham 7 owners. Access to the forum is limited if you are not a paid-up club member, but some very helpful information applicable to the Lotus Seven can be obtained for free.
- Last, but not least: firstname.lastname@example.org forum. An excellent resource for anything Seven with very friendly and helpful contributors and no guff. Some contributors race or raced their Sevens (Series 1, 2, 3, and 4), and really know the ins and outs of the car. Includes a very extensive library of past posts detailing numerous questions concerning a Seven, with helpful answers/suggestions from owners. (Originally started by Lotus Historian John Watson).