Under the Bonnet: Steering System Lubrication

A question commonly asked of us is how to lubricate the later MGB steering racks, which do not have a lubrication nipple. In searching for a definitive answer, I discovered that lubrication of these later steering racks is not a scheduled maintenance item, and as such, there are no “factory” instructions for lubricating them in service.

The instructions for a new or newly rebuilt unit are to stand the unit on end and pour 4/10 of a U.S. pint of Extreme Pressure S.A.E. 90 oil in the gaiter. Apparently the factory felt that the initial lubrication was good enough to last “forever”, as long as the rubber gaiters were intact. In fact, the only time these later steering racks require additional lubrication is probably when the gaiters are replaced, preferably before they get ripped, torn, or otherwise damaged.

The best way to lubricate these is to remove the old gaiters, run the rack out to one side, by turning the steering wheel, and pour a bit of 90 E.P. oil along the exposed rack (dribbles and spills will drop onto the newspaper you placed underneath), run the rack out to the opposite side, and install the new gaiter. Repeat on the other side. If you want to get more serious about this operation, remove the pinion damper cover, shim(s), and damper housing. Slowly add oil while the steering gear is turned from side to side. Before reassembly, check the damper pad for wear, and replace if required. Re-shim if necessary.

Early MGBs with a lubrication nipple on the steering rack housing get 10 strokes of an oil gun charged with 90 E.P. every 12,000 miles or every 12 months, whichever comes first. (On all MGBs, the tie rod ends and swivel pins are greased.)

DO NOT FILL THE GAITERS FULL OF OIL! The purpose of the gaiters is not so much to keep oil in, as to keep water, dirt, and other contaminants out. A gaiter full of oil will split, squirt oil all over the place, and/or restrict steering movement. The steering rack needs only to be lubricated – it does not need to run in an oil bath.

The MGB lubrication question prompted investigation into steering system lubrication requirements of other British sports cars, a summary of which follows. “90 E.P.” and “140 E.P.” refer to the appropriate weight of Extreme Pressure hypoid gear lubricant, otherwise known as “gear oil”. Where grease is specified, a general purpose “chassis grease” is fine. If your grease gun is loaded with high temperature disc brake bearing grease, this will work just as well.

Before oiling or greasing lubrication nipples, wipe the nipples clean first, and ensure that the end of the grease or oil gun is also clean. Do not over-lubricate. If excess oil or grease gets all over everything, clean it up before it contaminates your brakes and attracts dirt.

For more details on the following, such as frequency of service, consult your workshop manual.

MG TC – steering box :140 E.P. to nipple on top of steering box-steering joints: grease

MG TD-TF- steering rack: 90 E.P. to nipple in center of rack housing under car-steering joints (tie rod ends, king pin links): 90 E.P.

MGA – steering rack: 90 E.P. to rack housing Si pinion shaft nipples-steering joints: grease

MGB – covered at beginning of this article

MG MIDGET – steering rack, through approx. 1972 – 90 E.P. to nipple-steering tack, from approx. 1973 – grease (remove hex- headed plug from damper cap, install grease nipple)-steering joints: grease

AUSTIN-HEALEY – steering box (all models): 90 E.P. thru filler plug in top of steering box housing-steering joints, 100-4: 140 E.P.-steering joints, Sprite, 100-6, 3000: grease

JAGUAR XK120 – steering box & idle lever: 140 E.P.-othcr steering joints: grease

JAGUAR XK140 – XK150 – steering box: grease in nipple in racK housing steering joints: grease

TR2 – TR3B – steering box: 90 E.P. – filler plug in steering column 12″ above steering box-steering joints: grease

TR4 – TR6 – steering rack: grease – replace hex head plug in pinion damper cap with grease nipple-steering joints: grease (except TR4A TR6 trunnions, which use 90 E.P. – sec notes at end of this article).

SPITFIRE – steering rack: grease steering joints: 90 E.P. on trunnions, grease elsewhere Supplemental notes for TR4A – TR6:

With the change in trunnion design introduced with the TR4A. Triumph apparently intended to change the lubrication requirement from grease to oil. The TR4A Owner’s Manual specifics oil, but the TR5 Workshop Manual Supplement, TR250 and 1969 TR6 Owner’s Manuals specify grease. TR6 Owner’s Manuals from 1970 specify oil. Triumph became aware of the confusion they had created, and in 1972 issued a Technical Service Bulletin stating that all then currently produced Triumph cars should use oil in their trunnions.

INSTALLING STEERING COUPLERS

The rubber steering couplers used in Triumphs and Jaguars (Moss part #667-390) are notoriously frustrating to install, as their hole spacing is larger than the hole spacing on the parts to which they mount. This is a design feature to ensure that when installed, the rubber is slightly compressed, thereby avoiding the possibility of looseness.

A quick and easy way to install these is to put a hose clamp around them, tightened to the point where the holes in the coupler match the holes on the steering column attachments. The mounting bolts are then easily inserted, after which the hose clamp should be removed. (If you do not have a 4″ hose clamp handy, open up two smaller ones and join them together.)

by Eric Wilhelm



'Under the Bonnet: Steering System Lubrication' have 5 comments

  1. July 8, 2015 @ 6:10 pm Gary

    I’ve read that aftermarket steering racks have lube nipples like the older original MG racks; and that they use grease rather than EP90. I’ve also heard that grease makes more sense for all racks; it won’t wear off the lubricated surfaces; if the gaiters crack it won’t leak out; and synthetic greases have better water resisitance and provide higher lubrication than the old-style greases. My question: if you replace the EP90 in an old rack with grease, are there any real issues with safety or durability? Anyone have a REAL (meaning NOT a ‘religious’) reason why one is better than the other? All things being equal, grease makes more sense… a good synthetic grease will stay in place forever, and if the gaiters break you won’t screw up the floor of your garage… And after this discussion, let’s get into the Mac vs. PC debate…

    Reply

    • July 15, 2015 @ 9:33 am nikasj

      The best recommendation is to continue using EP90 on all original racks as its properties are much different than for modern greases. EP90 warms more quickly and disperses more effectively into a fine mist than does modern grease. The tolerances on the original components were designed for this “misting” lubrication and modern grease is far too stable to agitate as does EP90. While modern grease is longer lasting and a better lubricant for most uses, EP90’s unique qualities make it a better choice for original applications.

      Reply

      • April 22, 2017 @ 10:28 pm Peter Taylor

        Well I do not understand as EP90 or such, that is extreme pressure additives are very harmful to brass, one would not use EP oil in a gearbox with brass sincro.
        Some racks have steel bushings and some brass so be very careful what you use.

        Reply

  2. May 13, 2021 @ 1:53 pm jock McTavish

    HI . . I have run TDs for many years , but now have a silly leak from the pinion felt seal. . . I am very tempted to start using lithium grease . . anyone else done that ? it was recommended in the Sacred Octagon in 1986 !
    It is disconcerting to have a CLEAN. oil drip !! any ideas please ?

    Reply

    • September 1, 2021 @ 2:51 am Alan Ketchley

      The steering rack lube debate is similar to trunnion lubrication for Triumph GT6’s; what to use and how often. The “accepted” was EP90, not grease, and applied fairly regualarly as it eventually leeched out. I saw a post (found it once and then unable to find again) where someone recommended using Land Rover CV boot grease. It looks to be lithium based, but is a cross between thick oil and grease and can be appled with a grease gun. I used it on the GT6 and never experienced any issues or loss of lubrication. It could be a solution for MG steering racks.

      Reply


Would you like to share your thoughts?

Please note: technical questions about the above article may go unanswered. Questions related to Moss parts should be emailed to moss.tech@mossmotors.com

Your email address will not be published.

© Copyright 2021 Moss Motors, Ltd. All Rights Reserved.