Tuesday, 3 November 2020

Rear Brakes and Axle

Trying the keep pushing on with cleaning up the running gear and next up is the rear axle and brakes. 

Certainly was very dirty and rusty and quite a large section. Plan of attack was to start with cleaning up the axle.  

Decided to use a variety of weapons at my disposal. Rotary steel wire wheel brushes, think I must have bought at least 50 of these so far over the years. Also use the similar but more abrasive angle grinder version. Plain old wire wool to get into those corners and plenty of degreaser with my old toothbrush.

There was certainly a lot of crud!

Over the course of a few nights things started to clean up quite nicely.

While that was in progress I removed the hand brake mechanism and the brake pipes. Apart from a few rusty split pins that hold the rods in place all came apart without much fuss.

After that I moved on to disassembling the rear brakes to prepare for inspection and cleaning.

Firstly need to clean all the grease of the hub. Then undo the four nuts and remove the two lock tabs.

The brake drum comes away fairly easily with a screwdriver pushing against the backplate and working around the edges. Need to check for wear and any sign of a lip on the edge. Mine need to be replaced, but these are not expensive.

Then to remove the hub which is attached two the half shaft that connects to the differential.

You need to undo the single screw and that will allow the two hub sections to separate.

I needed to tap the outer hub away from the inner hub. Be care not to damage the two facing parts of the hub as they need to form a perfect seal to stop oil leaks. 

Now the hub and half shaft should come away easily. Check for signs of wear. I think mine look good.

On this face of the hub you will find a gasket and an O ring. These should be replaced if you have come this far. I found that the inner hub did moved ever so slightly, but it didn't when the outer hub was attached. I am hoping therefore that the bearings are good. They certainly don't make any noise and are smooth on rotation.

Then it is time to remove the brake pads.

These are held on by the spring loaded clips.

A screwdriver will help here.

Once they are removed the pad comes away.

And the same for the other side. They do suggest replacing these in pairs to keep the car breaking in a straight line and as I am replacing both drums the pads will also be replaced.

To remove the handbrake level you first pull the rubber gaiter off and check for cracks in the rubber. 

The level comes away very easily.

This then leaves the wheel cylinder and that is removed by unclipping this horseshoe clip.

You can see the bleed nipple here which can be unscrewed.

For both of mine the pistons were stuck fast so causing the brakes to fail.

But I found it quite easy to disassemble them and get them functioning again. First remove the rubber gaiter and check for cracks. Mine were in very good condition.

You need to remove one of the pistons by pulling it out. Some penetration fluid will help here.

Once out you can see the rubber O ring that forms the seal. Again mine were in very good condition.

Then using a fine grade of wet and dry paper I cleaned the inside of the cylinder.

All the other metal parts were cleaned with the wire wheel brush and came up very nicely.

They all fitted back together well and seem to function without any problems.

The only issue I had was trying to remove the manual brake adjuster wedge on one side. It took heat, penetrating fluid and the various clamps but it wouldn't budge.

I ended up welding the thread of a bold to it and the with two nuts managed to turn it though the hole. It took me about 4 hours to do!

Just need to finish cleaning all the parts and start to spray the axle with black chassis paint to protect from further deterioration.

Thursday, 8 October 2020

Front Steering and Suspension

At long last I can now focus some time towards restoring the parts for the MG Midget. My plan, now that the underside of the chassis is ready is to convert this lump of metal into a rolling chassis. To do that I need to strip down all the suspension and steering at the front and back and restore what I can and replace those parts that are too worn with new.

First up is the front steering and suspension. I took this off the car back in January 2013 totally covered in dirt and rust and both have been sitting in my garage ever since.

First off is to dismantle all of the components and then make assessments of each part. Initially wasn't going to post this on the blog, but then felt it might be useful to someone else as well.

Right then here we go!

Detach the wishbone pan from the kingpin and stub axle.

To do this you need to unscrew the fulcrum pin which is hidden behind this grease nipple and plug.

The grease nip should unscrew normally. It is worth testing to see if the ball bearing in the end still moves with a pointed tool.

Then unscrew the plug, mine is fairly corroded and will need replacing.

This exposes the fulcrum pin. A large flat head screwdriver should be enough to unscrew this, but it won't move until you have removed the cotter pin from the bottom of the king pin.

This nut should come off fairly easily.

What will be more difficult to remove is the cotter pin itself, because it will most likely be wedged in place and the only way to remove this is to hit the thread end of the pin which is likely to damage it. Fortunately these are replaceable and not more than a £2 including a new nut.

Now the fulcrum pin can unscrew. Luckily mine came out without much fuss.

It is now possible to separate the wishbone from the king pin and stub axle. The red circles are where I showed someone the screw points for the brake disc dust cover. The third bolt is hidden behind the brake disc.

Once separated you'll find these two cork seals on either side of the king pin which need to be replace.

Next I moved on to the wishbone and I needed to remove the rubber bushes

This was very easy and the rubber bushes need to be replaced but the bolt, washer and nut are all good.

Then on to removing the spring seat. These bolts were very rusty and stiff and required some penetrating fluid and long handled socket set.

Eventually it came off.

And that is the wishbone dismantled and ready for restoration. 

Now on to the stub axle, king pin, hub and disc.

First is it to slacken off the hub nuts

Now for whatever reason I didn't have either of the front dust covers that slot into the end of the hub. This obviously needs to be removed to access the hub nut. I'll be adding two of these to my shopping list.

Normally there would be a split pin holding the hub nut in place but as you can see that is also missing. I'll be adding two of these as well to my shopping list.

With the hub nut removed you can get access to the hub washer and you then need to remove that.

Then remove the four hub nuts so the hub is loose. Now the chances are that it won't slide off because the bearings are holding it in place. So you need to pull the hub off the stub axle.

There are specialist tools for this job, but I do have a valve spring compression tool and found this worked really well.

Now because my Midget has wire wheels my hub is longer than the steel hub this means that the outer bearing will probably be still in the hub, but the inner bearing will either still be in the hub or on the stub axle as shown here, which will need to be pulled off. Again there are specialist tools to do this but after removing the brake disc dust guard my spring compressor did the job. There is also the bearing seal which is fairly simple to remove.

I did have some real issues with my bearings on both axles. On one side a prior owner had fitted the outer bearings the wrong way round which meant they were extremely difficult to remove. You can just see in the photo below the outer case of the bearing (called the race) still stuck in the bottom of the hub. The inner part of the outer bearings came out because they were fitting incorrectly and probably over tightened which forced the bearing further into the hub. 

You can see here the damaged race of the bearing bent and pushing into the hub spacer. 

You can see here how the bearings have worn into the hub's outer spacer after I managed to remove the race. So I have no choice but to replace the hub. 

Now normally to remove the bearings you use a tool called a drift which is a metal bar that you can place in these cut out as shown in the photo below. Taping the drift gently either side will remove the bearing. On the wire wheel hub there are only cut outs next to the inner bearing which makes it more difficult to remove the outer bearing. 

I had to use a flat headed screwdriver to remove the incorrectly fitted outer bearing race. On the other hub as both bearings were fitted correctly both came out using a drift and hammer.

You will also find the hub spacer within the hub between the two bearings. Fortunately both of mine were not damaged at all.

Next up is to remove the king pin from the stub axel. To do this you have to first remove the top trunnion. This can be simply done by removing the top locking nut. On the trunnion there is a rubber bush that needs to be remove and in my case replaced with new.

The only thing left to remove is the dust cover at the back of the stub axle.

During the removal I noticed that there was an issue with the king pin bushes that sit in the stub axle. The problem with them is that a prior owner had fitted them incorrectly (similar theme with this car). On all four bushes there is a hole that needs to line up with grease holes in the stub axle. You can see below the bush as it was removed. The two holes should align when fitting.

To remove the bushes will require the correctly sized socket that matched the circumference of the bush. You can then press or hit to drive the bush out. I advise you use plenty of heat and penetrating fluid to help get these moving, but once it starts to move it does come out. It is likely that in removing the bush it will damage it and so will need replacing. If you do replace the bushes the king pin is unlikely to fit in the new bushes and will need to be reamed, which is the process of machining the bushes to fit the king pin perfectly. You can purchase or rent the tool to do this yourself. Here is a video that shows the process: https://www.youtube.com/watch?v=q-gdjnCpldI 

I have a specialist engineering company local to me that is going to do this for me.

Apart from the bearings this task was fairly simply. Some heat with a blow torch and penetrating fluid was definitely used on some nuts and getting the the bearings out. With everything disassembled it is now time to start to clean up and restore these parts.

Monday, 28 September 2020

Cavity Protection

Now that the underside of the chassis is fully painted with satin black chassis paint I wanted to add further protection to the cavities that lurk within the MG Midgets monocoque chassis. For this job I turned to Bilt Hamber's Dynax S50 (Other cavity protection waxes are available) because it also comes with a very useful lance that evenly sprays the wax all around the cavity walls.

The main areas requiring treatment include the whole rear bulk head that is very easy to access with the chassis on its side. MG very kindly left these holes behind to make this job so easy! 😉 I also applied a coat up inside the spring hanger area.

Other areas that need a coating include the cross member, between the inner and outer sills, front chassis legs, behind the foot plate, insides of the triangular supports, inside the a and b posts, inside the doors, under the front lip of the bonnet. or wherever the car is likely to rust, so basically everywhere! However don't spray this until you have painted that section as the paint will not stick to the wax and you'll have to thoroughly degrease everything!

I watched a couple of YouTube videos on how to do this to make sure I didn't waste too much of the product. 

The idea is to insert the lance right to the back of the cavity, start to release the wax and then fairly quickly pull the lance out of the cavity. The Dynax S50 is quite runny initially to allow it to settle into all the cracks and joints. I choose to apply two coats as I can still remember how badly rusted this whole area was.

Once dried the wax does have a tacky feel to it. So hopefully with the new metal, primer, chassis paint, seam sealer and now cavity protection this will last for a good few years.

Once I have completely finished the car I will probably apply underbody protection.