Sunday, 20 June 2021

Front Wheel Bearings Refitting

I thought I would dedicate a single post to fitting the front wheel bearings to my hub, because it was a bit of a mission and I thought I should pass on what I have learnt during the process.

Having wire wheels as I have, does make the whole process more difficult due to the length of the hub, but the main thing you need to be aware of is making sure you buy the best quality bearings that you can buy.

There is a very good reason for this which is that the tolerances involved in setting up the bearings are very small. If they are out you will get problems as I did.

As posted in this update back in Oct 2020 Front Steering and Suspension when I took everything apart I found that the hubs were badly damaged due to a previous owner fitting the bearings correctly. 

So I had to buy new hubs and bearings.


I'll explain how to fit them later in this post but what happened with this set of bearings was that once fitted and tightened correctly, the end of the hub wiggled around. Up, down, left and right. But not in and out along the length of the axle. This should not happen! I only spent £50 on a complete set of bearings for both sides, even though they were supposed to be for my MG Midget. They were not face adjusted.

After consulting with the MG Enthusiasts Forum we came to the conclusion that I had bought poorly manufactured bearings.

These are the original bearings, similar to what I pulled out of my hubs. 


In this picture above you're looking at the two 'faces' of the bearings. These sides face each other in the hub as shown below:

These bearings have been face adjusted, which means they have been specially engineered so that when the bearing is fitted in the hub there should be no movement at all and the inner and outer race should be level with each other.

All the parts are designed to be squeezed up together. They achieve this by making sure that on the face side the difference in height between the inner and outer race should be either zero or up to four thousandths of an inch. Now 1 thousandths of an inch = 0.03mm, so not very much at all.

I was given this guide from 1972 which helps to explain the whole set up:



With the help of a friend, who had a precision measuring gauge like the one below, we set about measuring some bearings.


First we measured an original bearing that my friend had. The one with the brass ring and the difference between the inner and outer race was almost unmeasurable.

Then we measured a set of bearings that one of the MG community had sold me after they found out about my issue. These bearings were designed for a slightly later model of MG Midget but were still face adjusted to provide engineering accuracy. The difference here was 4 thousandth on one and 5 thousandth one the other, so just within the limits.

We then measured the 'new' bearings I had bought that caused me all the issues and the difference on these was 12 thousandths of an inch or 0.3mm, which is quite a difference to the zero or up to 0.03mm that they should be. So with that result we knew these bearings were not face adjusted and so didn't tighten in the hub correctly and caused the hub to wobble around.

I would recommend that you try to source original bearings if you can. Reach out to the guys on the forums as they might be able to help you. Or failing that try to make sure you buy face adjusted bearings. I have been told that if you can buy a set of bearings with this part number they are the next best thing: GHK1142Q 

You can always measure them as I have done before fitting as it is a real pain trying to remove the bearings from these hubs without damaging them.

Fitting the bearings isn't really that hard. It does take time and if you have wire wheel hubs like me it is slightly more challenging when fitting the outer bearings.

First up make sure you grease the inside of the larger inner bearing, pushing the grease right down into the ball bearings themselves.


Then place the inner bearing in the hub. It is very important that you put them in the right way round. As I said earlier. The face goes down in first. You can see below the flange on the inner race that slides on to the axle.


The best way to push the bearing down is to use a bearing press which you can buy, but they are expensive. Or you can use a correct sized socket or if you have one you can use the outer race of an old bearing if you have one. Which I did of course! 

You need to tap the bearing down with a hammer. You have to be gentle enough to nudge it down but not too much to damage it. I tapped the bearing equally round the top edge to get it started. Then on the left and right side, two taps each to move it further down into the hub.

You will come to a point where the top of the bearing is flush with the hub. This is where you need the socket or outer race to drive this down to face in the hub. 


Place the socket or spare outer race on the bearing and continue to tap away until the bearing sets in place. You can tell when this is because the sound changes slightly when you tap.


Once in place you need to make sure you grease the bearings from this side, but not too much. You don't want excess grease here as I've been told that as the hub heats up the expanding grease can put pressure on the seal and potentially leak. So you only need enough to cover the bearings, but don't pack it in. 


Then fit the seal.



Next up is the inner spacer. These are the original ones and fortunately they were in very good shape. They measured exactly 1.5 inch. We did use a bit of wet and dry on a flat surface to ensure the ends were perfectly flat. 


Then you can coat the outside of the spacer in grease and drop it down on top of the inner bearing.



Now the spacer should be perfectly level with the hub's recess that the outer bearing sits in. However as mentioned above there is a tolerance of up to 4 thousandths of an inch and this is why you need good spec bearings.

If you have or can get access to a precision measuring tool like the one below I would suggest you check the tolerances before trying to fit the outer bearing.


If all is looking good then you can proceed with fitting the outer bearing. Again make sure you apply plenty of grease around the ball bearings.


And drop it down into the hub. Now with wire wheels due to them being longer you'll need a tool that will allow you to drive the bearings down into place without damaging the bearing.

I was told to make up a tool using a 15cm length of 25mm copper pipe. The idea is that you curve one end that matches the curve of the hub and bearing. 


Using a hammer to tap the top of the copper tool will slowly drive this down into place. 


Now I decided to use the old outer race from my old bearings again to protect my new bearings when tapping them down. But you must be careful because if you drive this outer race down too far it will get stuck in the hub. So use these race just to get the bearing down level initially the remove the outer race and then continue with the copper tool until it is in place, which again to can tell by the tone of the sound when you tap it with the hammer.


Then make sure the bearing is greased from this side as well and then you are good to mount the hub on to the brake disc.


Not much to this really. Tighten the four bolts. But try not to get any grease on the disc. If you do you'll need to thoroughly degrease it.




Then you can slide the hub into the axle. A few gentle taps with the rubber mallet should settle it in place. Even at this stage you should be able to tell if all has gone well. The hub should rotate without quietly and smoothly. 


After that you can fit the washer and castle nut.



Then torque to the recommended settings which you can find in your Haynes or owners manual. Do not over tighten the nut and it is important to note that the instructions say to tighten the nut to the correct settings and then to the align the castle nut to the hole in the hub to allow you to slide the split pin in. This might mean you need to slightly undo the nut to get it all aligned.


Using long pliers can you pull the split pin through and around to lock the castle nut in place.



Then fit the the grease cap.


I tapped this around the edge and not the thread so not to damage it. Make sure that when you rotate the hub the end of the thread is as close to dead centre as you can.


Once all that is done you can test to see if there is any movement other than a smooth rotation. Second time round mine seemed perfect. What a relief!


I could then fit my newly restored powder coated wire wheels for the first time in 8 and half years. It was so good to see them spinning freely without noise or any unwanted movement. 


Next up you can start to fit the brake callipers which is covered in this post: Front Brakes Rebuild and Fitting

Tuesday, 8 June 2021

Front Suspension Rebuild

After I had cleaned up all the suspension parts it was time to refit it all. I decided to buy new bushes and some of my fulcrum pins were threaded which I replaced.


First up is to fit the new bushed in to the lower wishbone. So started by applying the grease that came with the kit.


It is useful to point out that where the wishbone connects to the chassis there are two holes. One significantly bigger than the other. The point in this is that you should fit the inner bushes first.



Then slide the wishbone in place, push each bush in one at a time.


I found a well placed screw driver helped with this whilst using my knee as support for the wishbone.


You can the easily fit the outer bushes through the larger hole on either side, but depending on the type of bushes you have you might need to fit the metal tube first as further below.



I then used my welding clamps to insert the metal tubes that come with the bushes kit.



Once fully inserted I fitted the outer bush and then pushed through the fulcrum pin from the other side.




Then you can fit the large washer.


And tighten on the locking nut.



All ready for the stub axle before fitting the spring which is covered in this post: Front Steering Rebuild


Once you have completed fitting the stub axle and king pin it is time to fit the main front spring. However I need to be clear and make the following statement:

Springs under load are extremely dangerous and can cause major injury. I am not responsible for any accidents that may occur if you follow what I did to fit mine. If you are unsure about proceeding please speak to a professional.

I decided to follow the long bolt method as described in the Haynes Manual. This involves two or four long bolts. I bought these two 150mm bolts and added two further nuts to be safe. You don't need the bolts to be that long but that's what I went for.

The process is to undo the four bolts that hold the spring seat on to the lower wishbone. DO NOT undo all these bolts if the spring is in place! However you can use this method if you need to replace the spring by repeating this process in reverse.

Remove the spring seat and drop either two or four long bolts (depending how safe you want to be) down through the wishbone. 



You then lift the spring up into place and follow with the spring seat. Then start to tighten the nuts.



You will find that it is quite easy to start off with your fingers, but after a while you need another option. I found this video online that explains the whole process.


I followed his advice and used these mole grips and socket. 


You just have to carefully keep tightening both bolts evenly until the spring seat is in place and you can bolt in the original spring seat bolts one by one. 

Please watch the video as it was a great help to me.