Play in steering rack arm and clonk....advice required......

[berni29]

Hi

My plus 2 clonks when rocking the steering wheel. It is coming from the passenger side steering arm which actually moves up and down a fraction as it clonks. It is the end that goes into the steering rack that has the play. I have no idea what it all looks like inside a steering rack so am not sure what might be loose or if it is a "danger" situation. The rest of the rack is in very good condition with no play.

Does anyone recognise this and could point me in the right direction.

Many thanks

Berni

[type26owner]

Berni,
At the straight ahead position on the rack, the female pocket on the tooth is toast. That side of the rack is controlling the DOFs by the pinion gear and a saddle shaped sliding bearing on the opposite side of the rack. The rack will detent across the worn out tooth and move up and down just as you've observed. Replacement bare racks are available. I repaired mine by brazing the tooth groove with Certanium 71 and remachining the tooth profile back into the rack. As soon as Dave Bean got new ones in I bought one and put it away as stock.

One redeeming thing it won't get any worse. Once the tip of the tooth on the pinion gear bottoms out in the pocket of the rack it can't go any further. Scary design!

[RotoFlexible]

I've had to deal with this problem a few times. Most recently, I had to pull the rack and replace the bushings at either end. They are inexpensive and easy to come by (got mine from Dave Bean) but I had to take the rack to a machine shop for disassembly and to press in the bushings.

Another possibility is the ball joint that mates the end of the rack to the tie rod. This can wear and, if I recall correctly, can be adjusted. I replaced those parts at the same time I replaced the bushings. (This is for a baby Elan but I think the +2 is the same in this department except for the length of the tie rods.)

Hope this helps. Pulling the rack isn't much fun.

[type26owner]

Andrew,
The rack and pinions I've taken apart only have one bushing on the opposite side from the pinion. The only rack and pinion that has a bushing at both ends are the special ones used on the formula junior cars that I'm aware of. Dave Bean recently got some of those racks too and I bought and installed one in our Lotus41.

I'm planning on making a production run of unobtainium pinion gears in the next year or so. They are going to be expensive though but I need a new for the racecar. It's pinion teeth has large spalled areas now all the way around.

[tdafforn]

Replaced the socket part of the ball joint on my +2 a few months ago when it failed the MOT..
Simple anc cheap (Got some shims and the nylon socket from a truimp dealer nearby, cheaper than the Lotus dealer)
Cheers
Tim

[berni29]

Many thanks for the advice. It clonks whan not in the dead ahead position (maybe a bit less, not sure) so I am wondering if it could be the ball joint like Tim's. Did you have to take the rack out to fix that?

Many thanks again....

[gjz30075]

The rack can stay in place for any and all suspension work that is required, unless, of course the rack needs work, then it can come out.

Greg Z
'72 Sprint

[berni29]

Hi

I thought that Tim meant a ball joint in the rack...maybe he meant the track rod end.

[type26owner]

Pull the rubber gaiter back and have someone turn the wheel back and forth slowly while you watch what happens. Any play up and down of the tierod spherical joint end of the rack is a bad sign. If the spherical joint is loose that's easy to fix in place. There's small chance the play can be removed with the plunger and cap nut. The plunger usually wears a massive groove into the rack though and that's why there's vertical play. It can get ugly.

[gjz30075]

I thought that Tim meant a ball joint in the rack...maybe he meant the track rod end.

Whoops, you're right. I re-read his post and I'm sure that's what he means.

Greg Z

[type26owner]

It is the end that goes into the steering rack that has the play.

Isn't that clear enough? That is the end under the rubber boots. Is that correct Berni?

[tdafforn]

Hi Guys...
Sorry to be confusing..
It was the ball joint in the rack itself..
The socket is nylon and has to be shimmed
Cheers
Tim

[berni29]

Hi Keith...yes that is clear many thanks. As soon as I can I will do exactly as you suggest. The confusion was with Greg's posting.

[gjz30075]

Yep. So sorry for all the confusion.

Greg Z

[type26owner]

Berni,
The key to making the unit last a long time is to lubricate it with the best materials. It takes three different lubes to do it. Two greases and an oil. The oil is used on the sintered cast iron bushings that the pinion rotates in. A lithium based grease with moderate shear strenght should applied on the farend bushing constraining the rack and the plunger. The teeth of the pinion and the rack ONLY should have a thin coating of open or exposed gear grease. This stuff is unbelievably tacky and the shear strenght is extremely high. If this stuff gets onto the bushing at the farend it will sieze the unit. However it has a quality that the rack sorely needs and that is it stays put and does a superior job of lubricating the gears. Lubed in this way the unit will last several times longer I estimate.

Wear work clothes that need to be thrown away because the open gear grease will get allover you. Disposable gloves are a must too.