|
I have considered updating my original document but have not got around to doing it so the best I can provide is the following. Please to let us know how you get on if you do attempt to service your rack.
by AndyThomas on Tue Apr 27, 2010 9:09 pm
This is the orginal Richard Old article from Dolly Mixtures. There are some photos which I will attach latter.
Steering rack problems are a common MoT failure in our cars. These can be a split steering rack gaiter; excessive play in the steering rack itself or in the mounting arrangements of the rack. It is not that expensive to obtain a reconditioned rack but it is becoming more difficult. There was a time when any good auto spares shop could get one for you but even Moss Brothers have stopped supplying them. The other thing that encouraged me to have a go at overhauling my steering rack is that when you purchase a reconditioned item you do not know how thorough the reconditioning was. I would warn against going for the cheapest available as you may find that all that has taken place is that the outside of the item has been cleaned, it has been given a lick of paint and new gaiters have been fitted. If you decide to have a go at overhauling a rack yourself you may find that some of the bits are quite expensive but at least you know what has been done to the rack.
I have only worked on Dolomite racks but Andy has advised me that the main differences between the Dolomite and the Toledo rack is that the Toledo pinion has only 7 teeth and the Dolomite has 6 and that the teeth on the rack also appear slightly lower on the Toledo rack but are the same profile.
I must start by stating that I am an amateur car mechanic but I did serve an apprenticeship in the Ministry of Defence as an electrical fitter so I am used to servicing various electrical/mechanical machines. To undertake this task you will need in addition to the normal range of hand tools. A large solid vice mounted in a solid workbench; large spanners to fit the tie rod ball joint nuts and the rack damper plug; a gas torch; and a 1/4 UNF tap.
I have copies of the official Triumph Dolomite 1500 RWD parts catalogue, the 1500HL repair manual and a Haynes manual. The official manual lacks information when it comes to setting up the inner tie rod ball joints and the Haynes manual states that you adjust the number of shims to get the required amount of lift, play. I believe that the only way to get a pass from the majority of MoT testers is to set these up so that there is no play.
As usual the first task is to clean the exterior of the unit and once this has been done the real work can be started.
If you have been told the problems with the rack it is nice to confirm them next or to check if there are any other problems that need to be sorted.
Assuming that both track rod ends have already been removed, release the gaiter clips, and remove both gaiters. Having done this we are back into cleaning again. This time it is to remove the old grease from the parts that were covered by the gaiters.
It is time now to check for obvious wear. There are a number of areas where wear can cause problems. These are within each of the tie rod ball joints, and at both ends of the rack where the rack leaves the body.
Starting with the tie rod joints. If each ball joint is held in the vice the tie rod can be moved around to see if there is any play. I have purchased in the pass two reconditioned racks and I found it has been quite stiff to move their tie rods about in the ball joints. This may be the reason why some people end up with very heavy steering. If there is some play you will need to add some additional shims. Part numbers 130031 (0.0002th) and 130032 (0.006th), which cost about a £1 each. When I stripped one ball joint I discovered that the plastic socket that the ball joint fits into had split. Original part number was 120955, and has been superseded by part number 158732. These cost between £4 and £8 depending on the supplier, which seems a lot for just a piece of plastic.
When it comes to the play at the ends of the rack body, on the near side, non-pinion end, there is a bush fitted within the body of the steering rack that can obviously wear. To check this pull the rack fully out on the non pinion side and then grip rack body in the vice and check for play in the rack housing bush. If you are lucky you may find that there is no play and you will not have to withdraw the rack shaft from its body. If there is play you will need to replace the steering rack bush Part number 128002 @ £14. I have had to do this on the couple of racks that I have overhauled. I obtained them from Rimmer’s as it is not available from Moss Brothers.
Now grip the pinion end of the rack body in the vice and check for play at this end. When doing this it is more critical to check for play when the rack is in the central position as this is where the rack obviously spends most of its time and so obviously it is
more likely to wear at this point. If there is any play it is a matter of reducing the number of shims that are fitted in the damper and hoping that this will not result in the rack being easy move in the centre and too stiff to move at either end of its travel. If this turns out to be the case you will have to go for an exchange rack as there is wear in the centre of the rack shaft.
If you discover that the only wear is in the tie rod ball joints you might decide to just sort them out but I would recommend a full strip if you have got to do anything.
So starting with the rack damper assembly.
1. Remove the plug that secures the damper in the rack housing. I had to resort to the use of the gas torch to heat up the assembly before I could shift the plug and I suspect you will need to do the same as it is a steel plug in an aluminium casting.
2. Having removed the plug you can then remove the damper spring, the various shims and the damper.
Removal of the pinion
1. Within the plug that has just been removed there is an internal “O”ring, which is there to stop water and dirt entering the assembly. This needs to be removed and I would recommend that you plan to replace this item, Part Number 128021 @ a cost of about £1
2. There are two screwed holes in the side of the plug into which ¼ UNF bolts can be fitted to both lock the steering rack in the central position when refitting it back in the car or to assist in the removal of the pinion from the assembly. I found that the treads had rusted up over the years and that I needed to run a tap down the holes before I could get the bolts in.
3. Next invert the plug and fit it onto the pinion shaft. The two bolts can now be tightened so that they grip the pinion shaft and by using two screwdrivers the pinion shaft can be prised out of the rack housing. Once out the two bolts can be unscrewed and the plug removed from the pinion shaft.
4. On the pinion shaft there is a ball race, which will obviously need to be thoroughly cleaned out and checked. I have been lucky as once cleaned I have only needed to re-grease the ones that I have overhauled. If it needs to be replaced it is just a matter of removing a circlip and extracting the ball race. Part number 514901 or now part 21H5212 . It is a standard bearing number 6002 costing about £5.
5. The ball race is the top bearing for the pinion shaft and at the bottom of the pinion housing there is a simple bush that can be driven or pushed out. It is this bush that the grease nipple feeds so if you have routinely greased the rack you may not find any wear in this bush. To remove the bush part number 143823, first remove the grease nipple and then knock the end cover that the grease nipple screws into rack body. I used a bolt which just fitted through the hole in the aluminum rack to knock it out. It took me some time before I realised that the grease nipple screwed into an end cover that when knocked in would drive the bush out. A new bush costs about £1.40.
6. Having got the pinion out you need to carefully check the pinion gearing for wear. Noting that as the car is driven straight ahead for the majority of the time, there is going to be more wear in this position on both the pinion shaft gearing and the steering rack. I have been told that one of the tricks of the trade is to just remove the pinion shaft and to replace it back 180 degrees out. Obviously by doing this you change the contact point. The wear is still there but it is not in the dead straight ahead position. I have not found any noticeable wear and would suggest that if you do identify any wear it is time to give up with this steering rack.
Tie rods and rack shaft.
1. Grip the exposed rack shaft in protected vice jaws so that the lock nuts at both end of the rack shaft can be slackened and both tie-rod assemblies unscrewed from the rack. To do this I had to use a large hammer (4 lb) on the spanner as I found the lock nuts were very tight. You will find that there is a small coil spring at each assembly as you take them off.
2. The assemblies can then be stripped completely if the tab washers are bent back. Inside each assembly you will find a number of shims and a plastic socket
3. Once the lock nuts are removed from the shaft the shaft can be withdrawn from the rack body and inspected.
4. The official triumph repair manual states that there is a dimple in the rack shaft that can be used to centralize the racks shaft before installation in the car. This is achieved by removing the central plug from the thrust pad and using a length of stiff wire to locate the dimple in the shaft. Once located the shaft can be locked by fitting two ¼ UNF bolts into the pinion plug and gently tightening them until they pinch the shaft. Based on my limited experience not all shafts have this dimple so I would recommend you make a point of looking for it as part of your inspection as it may save you heart ache at a later stage.
5. Andy pointed out, and I agree, that it is well worth checking to see if the rack is bent. He held his rack in the vice and used a 25mm alloy ‘U’ section, which fitted perfectly over the rack teeth and the flat.
Rebuilding the rack
1. Replacing the rack nearside bush. If you identified that there was a need to replace the nearside bush you may find the following advice useful as I did have to think for some time before I came up with a successful method of removing the bush from inside the body of the steering rack as I did not have a long steel bar of the right diameter. In the end it was quite simple. I found a fairly solid washer that was the internal diameter of the rack body and I dropped this down the shaft so that it rested on the bush. Having done this I was then able to use a steel bar, whose diameter was not critical, to knock the bush out as the bar rested on the washer. Andy found that he had to cut a slot in the bush with a hacksaw blade before he could knock the bush out. He used a socket which just fitted inside the rack tube ( ~ 16mm) and the extensions bars to knock his bush out.
2. I then took some time to clean out old grease and muck from the inside of the body before I gave it a coat of black Hemmerite paint. Back to the fitting of the new bush. As I was not certain if the new bush was made of porous material I decided to leave it soaking over night in thin oil just in case it was before fitting. The actual fitting was just a matter of knocking it in carefully using a soft material such as a piece of wood to protect the bush from the hammer head.
3. Pinion. Replace the end cover with grease nipple in the lower end of the pinion hosing. Fit the lower bush, ensuring that the recessed end of the bush is fitted adjacent to the end cover.
4. Having again made certain that all parts are clean thoroughly grease all the parts and insert rack into the rack body. Having achieved this refit the pinion. Next fit the pressure pad, spring, shims and cap nut to the rack tube. Do not forget to fit the new O ring in the cap nut before fitting. The Haynes manual states the shims should be such that there is 0.0006 inch of end float in the pressure pad. As already stated I believe that modern day MoT testers do not like any end float, play, so it is best to remove shims until the rack movement starts to stiffen up. Andy found the best method to remove the play was to assemble the cap nut with out the spring, adjust the shims to remove any play and ensure the rack runs smooth with no tight spots and then reassemble with the spring which will tighten it up futher. To be specific if you have a spring balance the Haynes specifies that the rack pinion should not need more than 24 in lbs to move the rack at the ends which tend to be harder to turn if there is wear in the centre. The cap nut has a plug (nut) in its centre, which can obviously be removed and replaced with a grease nipple. None of the manuals suggest it but my recommendation is that if you obtain a grease nipple part number 056935 at a cost of about £1 and pump grease into it as this gets to the heart of the rack where the damper acts on the rack shaft. I was surprised by the difference it made, in respect to ease of movement when I pumped grease into the rack at this point. Unfortunately you cannot get at this grease nipple once the rack is fitted in the car so having used it to pump grease into the rack it is a matter of taking it out afterwards and fitting refitting the plug.
5. It is now time to pack with grease and rebuild the inner tie rod ball joints. As I stated earlier the Haynes manual indicates that these should be set up with between 0.0005 and 0.003 inch lift (play) in them but I believe that it is just a matter of adjusting the shims so that the ball joints are fairly stiff to move if you want the average MoT tester to pass the rack. However remember if you make the ball joints too stiff your steering will be stiff. A point to watch out for is that the ball joints may initially feel quite tight but once you have moved them around they may free up. I think this is due to the grease being squeezed out from between the ball and the plastic seat to a certain extent. Removing all play, obviously defeats the spring action within the joint but my attitude is that if this keeps the average MoT tester happy, so be it. For safety the nuts have to be torques up to 80 lb ft and do not for get to fit and turn up the tab washers. Part number 120957 which cost about £1.50
6. The final stage is just to apply more grease to everything and to fit the new gaiters. I suggest that you put a few turns of insulating tape on the end of the near side rack body before you fit the gaiter to this end as I have found that there is a tendency for this gaiter to slide off the rack body. A few turns of insulating tape will help to stop this happening. When it comes to the gaiters. I have noticed that some gaiters are of a slightly bigger diameter than others. The larger diameter gaiters have a tendency to rub on the suspension bracket. This then results in a hole being rubbed in the gaiter. The two Rimmer’s reconditioned racks that I have purchased have come with the slightly smaller in diameter gaiters, which do not suffer from this problem. However they do still split with use. I was tempted to purchase the gaiters that I needed for my recondition from Rimmers to see if they would be the smaller diameter gaiters but in the end Moss Brothers got the order because they were so much cheaper @£7.95p and it is not too difficult to replace them in place.
7. Also at this end of the rack, near side, there is a small hole in the body of the rack under where the rubber (or poly) mount goes. It should have a simple plug (disc) in it, which is then taped over to keep the plug (disc) in place so as to stop dirt from entering the rack. I do not know why the racks have this hole. Can anyone tell me!
Finally it’s just a matter of centralizing & locking the rack by fitting the two ¼ inch UNF bolts once again into the rack damper plug so that it is ready for refitting in the car.
|
Register
Login
FAQ
Search
