November 2007

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Getting Back to a Rolling Chassis 

At the end of the last report the chassis was nearing its repair work and was ready for reinstallation of the front and rear suspension. At the same time I completed the conversion from steel to wire wheels, restored and fitted the fuel tank, new brake lines and hand brake system. Oh and in between I finished stripping the engine block.

Front Suspension 

Reassembly of the front suspension begins with the lower wishbone pivot being bolted to the chassis. Remember to make sure that the wishbone ends are clean and free of rust and any rough areas.  Next step was to install the wishbone arm bushes. As you can see I have opted for Polybush polyurethane bushes rather than the rubber/steel MGB V8 option. I will let you know how they work out

Next step is to fit the arms. Remember that if you are fitting an anti roll bar , as I am, that the front arm is a special with one  enlarged spring pan bolt hole and has extra reinforcement. Only loosely tighten the retaining nuts at this stage.

Here the spring pan is in and  bolted up but not to final torques. Note the anti roll bar drop rod is fitted. 

I choose to replace my king pins as the originals were badly corroded in the bottom threaded areas. I got an experienced work shop to press out the old and in with the new. This needs to be done correctly for obvious reasons. They also crack tested the steering knuckle for me afterwards. The trunions have a bushing that, if renewed, needs to be reamed to an exact size. Barney Gaylord's website mgaguru.com  has an excellent set of pictures on how to do this.

Here the top and bottom trunions are going on. The tube shown, when pushed in allows the trunion to only rotate a limited number of times. It also carries the main pivot bolt at the top and bottom. Not the rubber gaiters. These can be tricky to install and have a surprising amount of grip on the kingpin and need silicone lubrication to get them to slip as the kingpin rotates.

Here is a king pin ready to be fitted. Remember the kingpin threads are left handed for the left side of the car and right handed for the right side of the car. (left and right side is when you have the engine in front of you and the boot (trunk) behind you.

Above are the fulcrum bolt components. Rather than attempt to explain the sequence of installation its better to refer to the work shop manual

Here the shock absorber is bolted on and the kingpin assemblies bolt threaded through the top shock absorber arms.

Here the spring is in. Remember to grease the spring top and bottom. There are a number of ways of compressing the spring to the point where you can get the bottom kingpin fulcrum bolt in.  As I had no engine in I opted to use two coil spring compressors with the top hooks over a pry bar behind the bump stop and the bottom hooks under the bottom spring pan.

By winding up equally on the coil spring compressors both sides up came the bottom pan until I could get the lower trunion in between the lower arms. Note the for safety I still tied off the coil spring just in case something broke. This way the spring would be held and prevented from bouncing round the garage. 

Here is the finished set up with bottom fulcrum bolt in and the spring compressors removed. Again you can see the new anti roll bar drop rod and the reinforced lower suspension arm.

Here I have pushed on the new front hub assembly complete with new disc. I have not detailed out the process of fitting new oil seal or bearings as it is a very straight forward process. At this stage the hub nut is loosely tightened.

Here is how the front now looks with wire wheels. The suspension components are only finally tightened when the car has everything reinstalled

 

Back Axle 

Having counted the number of splines on the old disc wheel axles 7 times I found that my MGA was one of the batch that was assemble using 26 splined axles. As I am fitting wires and you can only get the new rear hub/axles assemblies as 25 splined I has to change out the sun wheels in my differential. Step one was to get the diff assembly off the back axle You can work with the assembly still in the carrier with just one bearing cap off but I decided to take it out completely. First drill out the area where the small retaining pin is peened over and then drive it out from the other side as shown. The pin can only go in and out from one side. Next step is to drive out the large sun wheel pin. The small retaining pin is the only thing that holds this in place.

The four sun wheels and thrust bearings can then be 'walked out' of the assembly. Its a fiddly job but relatively easy

The first two with the 25 spline teeth go in first . Replace the thrust bearings at the same time. Again Barney Gaylord has an excellent section on the procedure that gives a lot more detail than I am showing

Here I am attempting to illustrate how to easily get in the two 'floating' sun wheels. I found it easier to place both on opposite sides in the open areas of the cage and then rotate them both on the other two 'splined' wheels until the move inside the cage where the big pin will fix them in place. The small pin is replaced and the open larger end peened over to prevent the pin from coming out. 

Next job was to remove the rear hubs

 

First bend down the lock washer tab and use the special large socket to undo the nut. Remember we have left and right hand threads here as well. The nut is stamped LH or RH so no excuses. Mine took a breaker bar and an extension tube to release which is good.

Here is the puller set up I used to ease them off. They were tight but not in any way frozen in place.

Here is the hub off revealing perfect bearing unscored bearing surfaces.

Next off came the brake back plate for cleaning and painting.

Out with the old bearing and oil seal and in with the new

Here is the old rear inner hub with new shorter wheel studs, necessary for the wire wheel conversion outer hub. The other device is a bearing driver that has been invaluable for get bearing and oil seals in and out

Here is the restored back plate / hub reinstalled. Remember to put the brake back plate on before the hub!

I've jumped ahead a bit but I wanted to illustrate the sort of serious leverage needed on that nut to tighten it up. 

Rear Suspension 

There is a lot of debate about springs and what value the arch should be. My old springs were sagging on the drivers side and as new ones were not available at the time I had them retempered by a company in the UK that still makes springs and a good job they did to

The problem I have is to know if the camber is correct or not because to play safe I told them to keep the camber 'as sent' on the basis that it looked ok on the original car

Here is the car with the new wire wheel hub/axles installed. Again I have not detailed it because it was such a straight forward process. Just remember to fit the rubber o rings and new paper gaskets

On the left are my brake drums and as you can see they are different! . They are same size but are of different weights. I assume some over jealous mechanic managed to break one getting it off at some time. New drums have been installed.

Fuel Tank 

Time to look at the fuel tank. Above is the tank before cleaning

 

Closer inspection revealed that some one had fibre glassed over some areas where the tank had rusted through and had obviously leaked at some stage!. The area can be seen in the photo. Its the lower edge when the tank is installed that conveniently collects muck and moisture from the rear wheels. Small pin holes had developed that can be seen in the photo

I thoroughly cleaned the areas and checked for any other weak areas and then used an epoxy compound called liquid weld that has fuel tank repairs as one of its uses. I basically filled the complete lower edge in order to seal the pin holes and form a radius to prevent dirt from collecting in this area again.

I also chose to seal the inside of the tank and here it is draining out surplus sealing liquid. Its like varnishing the inside of your tank. You get into some interesting positions swilling the liquid around that tank. Remember to blow through the fuel take off fitting to make sure that you don't seal it up!

Here is the tank installed in the chassis with new straps. These were a pain to fit and needs some perseverance to get them to fit. Remember to put the spacer tube between the two tabs on the chassis cross tube. (see left) Its a sod to get in.

 

 

Hydraulic Brake System & Handbrake

Here we have the refurbished front disc brake calliper installed. Note the location of the brake pipe and the special bracket the prevents the brake pipe from turning. Not advisable as loosening could cause your brakes to leak fluid and loose pressure.

Here I am showing the routing of the new copper brake lines around the engine bay.

Here I am showing the routing of the new copper brake lines around the rear axle area.

Here I am showing the routing of the new copper brake lines around the rear axle area. Note how the handbrake cable (thick black line) is spaced down lower than the copper brake pipe.

Note how the copper brake line from front to back dog legs inboard of the rear front spring mounting point. This avoids the danger of people jacking the car up on the brake line and crushing it.

Again these are general views to show how the copper brake pipes and hand brake cable run

At the back of the axle the handbrake cable connects to a fulcrum arm. On my can this was very sloppy through excessive  wear and I chose to replace the pin and rebush the fulcrum arms. Note the pin screws in to the bracket. It is not a pin held there by the nut at the back

Here is the rebushed assembly installed and well lubricated with Coppaslip. It is now nice and taught and ready for operation.

This picture shows how the handbrake cables are connected to the lever arms on each of the back brake drum hydraulic cylinders.

 

 

All stuff on this site Copyright the Barbers, December, 2007 .
For problems or questions regarding this web contact mga1600@btopenworld.com
Last updated: 05/12/2007 .