Bradford wobbles

[John Wolf]

Hi Mike, I worked for International in NZ in the 70's and we had AB110's (forerunners to the C1100's) as service vehicles but I can't recall ever experiancing a shimmy in the steering, however I do believe that you are correct when you say that the axle alignment outboard of the spring pads may contribute to the problem.

I have resisted tweeking the Bradford axle because the truck wheel alignment guy I spoke to told me you get one shot at bending the axle like this, and secondly I don't have the data that gives the alignment specs relevant to the spring pads, so I opted to fit a VW steering damper.

Is the king pin alignment data for the bare Bradford beam axle available ?

John W

[Keith Andrews]

Is the king pin alignment data for the bare Bradford beam axle available ?

And If thyat is avalible it doesnt mean it would be relivent to modern radial construstion tyres....
The introduction of radial tyres changed the basis of of modern wheel alignment specs in caster and chamber.

[Forumadmin]

In what way did it change the specs. on castor and camber? I accept that the lower profile of radials would alter the steering geometry and move the contact patch outwards (thus needing more offset) and also that more deflection in the sidewall of radials would mean that more camber would be needed to keep the wheel vertical on the outside wheel.
But how would the castor be affected?

[Mike Allfrey]

Dear John,

Not at all sure about that, but would think that the data would be shown on the works drawing for the front axle beam. Such could be in the JCC archives somewhere. Barry Emms (NZJCC) has written quite a piece on the Bradford steering system.

What you see below is mostly what I have used in my Technical Notes Series that I compiled into one document. Thanks are due to Barry for his interesting writing in Flat Four.


THE STEERING SYSTEM
The steering gear is of the Bishop cam and lever type, and requires periodic lubrication of the box, using the appropriate oil (Penrite Steering Box Lube = 600 Weight Grease - Self Leveling). The felt bushing at the top of the steering column should be oiled (Engine Oil) lightly at 5000 mile intervals.
Models CA and CB – Adjustment for wear in the steering box was by shims between the side plate and the steering box housing, which when removed, pressed the follower further into mesh with the cam. Shims are of two thicknesses, 0.003” and 0.005” and must be flat and clean when being used. Movement of more than ½”at the steering wheel rim indicates excessive play, and shims should be removed and/or swapped for different thickness shims until play is removed. It should be noted that wear takes place more in the centre of the cam than at the two extremes, and care should be taken to ensure that the full range of wheel movement is obtained after adjustment.
Model CC – On this model a modified side plate was fitted, having a grub-screw, fixed by a lock-nut, which bears on the end of the follower. Adjustment is made by slackening off the lock-nut and screwing in the grub-screw until play is eliminated. While making this adjustment the steering box should be relaxed in the full lock position.
Castor and Camber Angles – Castor angle is incorporated in the design of the road springs, and is 2½°. Camber angle is allowed for in the layout of the stub axle, and is 2°.

Steering Wobble – This condition may be experienced even if the steering gear seems to be in good order, and without perceptible signs of wear. In such cases a cure may be effected by fitting tapered packings between the front axle and the road springs. The taper should be, over the length of the spring support, be from zero to 1/8”. Some vehicles suffer from excessive castor and in such cases, the wedge should be reversed. (Taper should be fitted with the1/8” end to the front)

Steering Track-rod (from Barry Emms, New Zealand) – An important part of the steering system is the connection between the front wheels. On the Bradford, this a hollow tube fitted with a spring loaded ball joint at each end and is known as the steering track-rod. One end is threaded so that the length of the track-rod can be adjusted. This adjustment is provided to set the toe-in of the front wheels. It should mentioned that the reason for toe-in is to allow for normal wear of steering components. The theory is that as the vehicle moves forward, the front wheels are forced backwards, hence taking up a straight ahead position. Excessive wear at either of the ball joints or incorrectly set toe-in will cause the vehicle to wander on the road. It will also cause tyre wear, usually indicated by individual tread lines worn on an angle. The best way to approach problems with the track-rod is to remove it, strip and clean all components, replace as required and then rebuild. This can be carried out as follows:
1. Position the vehicle on a firm level surface. Firmly apply the park brake and jack up the front axle. Support the beam of the axle on solid wooden blocks at each end. Never work underneath a vehicle that is only supported on a jack, it is dangerous.
2. Remove both front wheels.
3. Clean all dirt and grease off the steering arms and the ends of the track-rod to expose the split pins. Unscrew the grease nipples. Use a length of 5/16” flat steel in the slot to facilitate unscrewing the end cap. Alternatively, hold the piece of bar end-on in the slot and use an adjustable spanner to unscrew the end cap.
4. The track-rod can now be pulled off the steering arms. One half of the seat falls out first followed by the steering arm ball. The inner seat and spring are lodged in the track-rod.
5. The inner seat may jam in the recess and may require driving out with a small sharp cold chisel via the ball slot. Smooth out any nicks with a fine cut file later.
6. Keep the end cap, seats and spring from each end separate so that they are assembled on their original end of the track-rod.
7. Clean all parts so that the components can be checked for wear.
8. With the pair of seats held in position over the steering arm ball, there should be a vertical gap between the seat faces of 1/8”. If this gap is not present, the seats are too worn to be serviceable.
9. Before progressing further, measure and write down the end to end length of the track-rod. The track-rod should be straight and if not, any bends must be removed. One method of straightening the track-rod is to support each end on wooden blocks, with the high point in the bend just between the blocks pointing up. A controlled thump with a heavy piece of timber held vertically will help to remove the bend. An engineers press with suitable blocks can also be used.
10. Loosen the pinch bolt and unscrew the threaded end. To make the toe-in adjustment easier, clean-up the thread with a wire brush and make sure that the two components can be screwed together freely.
11. Measure the depth of the recesses in each end of the track-rod. This dimension should be exactly 2½”. In diagram ‘B’ is shown the dimension of 2 7/16” (2.4375”). Holding a pair of seats on a steering arm ball and measuring the overall length can check this dimension.
12. It should now be apparent that the seats can float when correctly assembled into the track rod. This endfloat is not easily seen as the spring holds the seats and ball assembly firmly against the end cap. There should be 0.0625” of movement at the spring. If the steering arm ball has worn to an oval shape, the inner seat would move a small amount as the steering arm is operated. In the normal condition the seats would only move to compress the spring if the road wheel transmitted a heavy load to the steering arm.
The free length of the spring appears to vary between 0.75” and 0.875”.
13. Should the springs not hold the seats in firm contact with the steering arm ball, it would be permissible to space the spring outwards by use of a suitable flat washer. Care should be taken to ensure that, after assembly of the joint, there is the 0.0625” end-float. The spigot on the end of the inner seat should fit into the inner diameter of the flat washer. The spring should be compressed 1/8” (0.125”) when the ball joint is assembled and the end cap fully tightened.
14. The track-rod ball joint should be thoroughly lubricated with a good quality lithium based grease during assembly.
Note: A new pair of seats and a new spring can be borrowed so that wear at the original components can be determined. In some cases it could be that the new seats are longer than the used set on hand. Their overall measurement when fitted over a steering arm ball may be 2.59375” with the gap between the facing surfaces the same at 1/8” (0.125”). This type of ball joint is designed such that the end cap butts against the end of the track-rod when fully tightened. Should the new seat assembly be longer than the track-rod recess, the end cap would take up all the play in the joint prior to being screwed fully home. This is a very dangerous condition because the end cap would need to be left loose on the thread with just a small split pin securing the joint.
The problem with the longer seat assembly can be over come by using the following method:
a) Assemble the ball joint without the spring and note the length of seat protruding from the end of the track-rod while being held firmly into the track-rod.
b) To this measurement add 0.0625”. This sum is the amount that must be removed from one of the seats.
c) Using a lathe, machine off the calculated amount from the inner seat’s spigot. This will increase the spring’s tension on the seat, so a corresponding amount of metal will have to be machined from the spigot shoulder.
d) The seats should be assembled into the joint without the spring, but with the end cap tight, to verify there is some endfloat at the spring loaded seat.
15. Assemble each joint and tighten the end cap fully. It should be noted that, if new seats are used, a hole will have to be drilled for the split pin. After the drilling operation, the joint should be disassembled, the hole ends deburred, drill swarth cleaned out and components lubricated ready for final assembly into the vehicle.
16. Screw the end into the track rod, to the overall length dimension previously written down. Adjust the length making sure that the ball slots are properly aligned.
17. Install the springs and the inner seats. Install the track-rod assembly is repositioned so that the adjustable end is located on the RHS (driver’s side) of the vehicle. Push in the outer seats and fully tighten the end caps and secure with new split pins. Do not prise open the pin on the RHS joint. It may need removal later.
18. Replace the road wheels and lower the vehicle to the ground.
19. The toe-in can now be adjusted:
a) Set the wheels to the straight ahead position. Mark the inside of the tyres with cross, using chalk or a pen.
b) Roll the vehicle so that the marks are just below spring height at the front.
c) Accurately measure the distance between the two marked crosses. An old car radio aerial is useful as it can be set to length easily and then measured with a good quality tape measure.
d) Roll the vehicle so that the crosses are towards the rear and about the same height.
e) Accurately measure the distance between the two crosses. This dimension should be 1/8” (0.125”) greater than that taken at the front.
f) To adjust the toe-in, unscrew the RHS end cap and lift the loosened assembly from the steering arm ball. Screw the threaded end out to increase the toe-in, screw it in to decrease the toe-in.
g) Once the correct toe-in has been set, re-tighten the end cap and the pinch bolt. Make sure that the two ball slots are aligned. If the slots are not aligned then, as the wheel is moved, wear will occur at the slot edges and the ball neck. Carry out items c) to f) to verify that the toe-in is correct. When it is correct, install the split pin and prise it open a small amount. There is a 1/16” (0.0625”) tolerance at the toe-in adjustment.
h) Install new grease nipples and lubricate the joints thoroughly. Wipe away excess grease. Regular lubrication here will keep the joints properly lubricated and will also force out any dirt and moisture. In dusty conditions it is wise to increase the lubrication frequency to prevent wear taking place.


I note mention of radial tyres in this topic. Radials, on a Bradford? I have a fair amount of concern about radial tyres on Jowetts. The cars were never designed for such an application and, I believe, the wheel centres are to thin to cope with the higher grip characteristics of the modern tyre. My Jupiter is very satisfactory on cross-ply tyres. I used to use Dunlop C-41s from Zimbabwe, and then Robert stuffed up that source. The current tyres are Excelsiors from India which are reasonably stiff in the walls. Olympic, here in Australia used to make a two-ply 5.50-16 tyre that was rated as a four-ply. It was extremely soft in the side wall area and the Jupiter felt super-nervous on those. I bit the bullet and bought a set of the Dunlop C41 tyres and things improved greatly.

I hope the information above helps the cause!

Regards,

Mike Allfrey.

[Forumadmin]

I agree with Mike on the wheel centres being too thin when wider than standard radials do crack the wheel centres, although after 50 years of abuse they might have cracked anyway. I weld a bead around the stud holes and the hub cab fixings and around the web holes on the Jupiter. This does seem to cure the problem. I also fit stronger studs for competition as the standard ones stretch. But yes we are exceeding the design limit!

However, I do think that the extra rubber does make the car safer. I have not fitted top quality crossplies ever on my Jowetts; but do have standard 1970 Henley crossplies on the Javelin. These certainly give a taste of how the car did perform. I will, once we have the new garage finished, put a steering geometry check for the Jav on the list of jobs to do as I suspect that not all the lack of handling is down to the tyres! I frequently changed the wheels on the Jav to radials and noticed much better braking and cornering, but the amount of rubber on the road was probably double.

I have ordered the roof frame and cladding today so as to get the site water tight before winter! There are 5 Cubic Metres of ballast and cement waiting for the floor as well. So the Jav is behind a list of jobs waiting for the team during the winter.

[Keith Andrews]

Cost of cross plys here are more expensive the big wide tyres I have on the Camaro...
I cant rem or find the info re old cars camber caster etc
But if u look up the old specs of say 1920s/30s fords, dodges etc and compare to modern specs, everything thing is damn near opposte..even my camaro has very different specs to factory cross plys
Also back in the late 60s early 70s on cars like morris 1100s and early minis and the introduction of radials issues where found in handling because the crossplys had far stiffer walls than the radials, and the recommended soln back the by the NZ Motor corp /British leyland was to increase air pressure up around the 40 to 45 lb

The steering gear is of the Bishop cam and lever type, and requires periodic lubrication of the box, using the appropriate oil (Penrite Steering Box Lube = 600 Weight Grease - Self Leveling)

Is this a grease??? Bradford steering boxes where notorious for wear, and I believe I found out why....
Most had a grease nipple and when serviced it was ASSUMED it was to be greased with the grease gun..
In a service manual, a single obscure sentice, it meantions to service with a grease gun with 90 (from memory )weight oil in it.
Basic engineering will tell u if it has gease in it the side presure will force the grease away from the shaft and bush, and will not flow back, resulting in shaft to bush direct contact and wear....hence using a heavy weight gear oil not grease.

[Mike Allfrey]

Dear Keith,

I agree with your comments. However, the Penrite Steering Box Lube is a very thick and clingy oil. I use it in my Javelin and in the Jupiter's steering rack. I also use it in the upper front suspension link containers. It appears to work well. I grease the kingpins with it too.

I also understand the cross-ply tyres being expensive, but in reality, they are cheap. Here in the world's number one Nanny State we are so restricted by speed limits, ultimate road holding should not be a problem.

By the way, this year so far, I have been fined twice for exceeding the posted speed limit by 2 kph. On top of this, along our freeways (motorway goat tracks) there are a number of illuminated signs with the following legend:

"POLICE ENFORCING SPEED IN THIS AREA"

Now, that is creative!

Mike A.

[Keith Andrews]

However, the Penrite Steering Box Lube is a very thick and clingy oil

I am not questioning the penrite steering box lube grease as Im not familar with it or its properties...just the practice of using lube grease in steering boxes because there is a grease nipple.
As to price of cross plys in NZ oh yeah..damn near 2x the cost of a cheap 14x 60x 235 radial for the camaro, and thats over 1000 bucks a set not including the spare...
As to performance benifits of a radial in a Bradford....well we really need 'performance' in the 1st place..rather a moot piont there lol
I have run both, and the crossplys give a firmer harder ride, and if the radials run around 45lbs the stabilty of cross plys in cnrs...other wise itsa like running the Camaro on 14x 205x 60s (close equilient of the factory crossplys)..kinder wobbles down the road on the soft walls...but doesnt on the factory crossplys...Thats body wobbles not the bradford sterring wobble to clairify

Back to the Bradford wobbles....
Going on all the experiance, of guys in NZ, some who fought the VW damper to the end, my own knowledge, investigation and research over the yrs...what is what is not....my firm conclusion is the same as the recent diehards..
For get bending the axle wedging what ever....just put a damn VW damper in and enjoy the drive...
And If a stickler for 'orginality' when u get to the show, simply unbolt the damn thing and hide it in the bottom of the picnic basket lol