Tuesday, January 14, 2014

Rear Subframe Installation

Well the day has finally arrived. The day when I get to put the rear subframe back onto the car. It seems like an age since it was removed, but I was taking my time. However, there is now a bit of a rush to get the car roadworthy again. As mentioned in a previous post, we are having building work done and the Mini is really in the way and at risk of being damaged. So I need to get it back on it's wheels asap so it can driven to the garage of a kind friend for a while. (Thanks John)

To get the car to a driveable state, there are several (well actually loads) of things that need to happen:
  • Underseal the rear of the car 
  • Cut a hole in the subframe for the rear exhaust mount
  • Tidy inside the boot when the subframe bolts go
  • Attach the subframe to the car
  • Attach the handbrake
  • Bleed and set the brakes
  • Install the petrol tank
  • Attach the exhaust

I know! A mammoth task for one day, but that is all I have as I've taken a day off work to get all these jobs done.  Working alone, I wasn't sure if it was possible, but it is amazing what you can get done if you are pushed.
I did contemplate braking this post up into different sections, but seen as how all the work was done at once, it seemed fitting that it all is detailed in one post. So this is a long one . . .

Underseal the rear of the car 
To be honest, I had already done a large amount of this a few days before with a can of Tetroseal and a brush. All I had to do today was to get into those awkward places with the aerosol version. I got out as early as I could and sprayed into the nooks and crannies, especially into the rear valance. I have to say, it was bloody freezing, to the point where my fingers were killing me.

Cut a hole in the subframe for the rear exhaust mount
After the freezing cold job, I moved indoors to the welcoming warmth of the living room to work on the subframe. As detailed in this post here, I have filled the rear subframe with expanding foam which has obscured the hole for the rear exhaust mount. It was simply a job of locating the hole in the subframe. Then drilling into the foam wide enough to accept a bolt and socket. Then I could attach the cotton real exhaust mount onto the subframe. Just to be on the safe side, I covered the hole over with a weather proof tape.

Hole in the foam for the bold that hold the rear
'cotton reel' exhaust mount to the subframe.

Tidy inside the boot where the subframe bolts go
In each corner where the subframe bolts sit, it was a bit tatty, so this was just a quick spray inside the boot to make it look a bit more presentable.

Attach the subframe to the car
This is where the bulk of the work was for me. (Along with the exhaust, but comes later!). Like so many other things on the Mini, I have never done this before. So I was a little unsure how easy/difficult it was going to be. I had read around the subject, but there is no substitute for experience, and I had none.

The method I adopted was to use two trolley jacks either side of the subframe to lift it into place. This way, I could maneuver each side independently with quite a fine degree of control.  

Using cloths over a small piece of wood, I lifted the subframe onto the jacks. There is a balancing point front to back where the subframe will sit without needing to be held. Once I had that balance, I slid the jacks under the rear of the car.

You can see in the pic below that I used some string to tie up the radius arms. It would have been a nightmare if they were left to swing about.

Using the jacks, I was able to align the subframe trunnion holes upto the fixing points on the car and was able to get in the first shiny new stainless bolt with a fine helping of copper slip.

Leaving the first trunnion bolts loose, I worked on the other side and the two rear mounts getting all the bolts in place and finger tight. Once I was satisfied that the position of the subframe was OK, I made sure all the bolts were torqued up and was finally able to remove the jacks.

This seemed fairly straight forward, and apart from a little awkwardness locating the bolts, everything went to plan. It was time consuming though and for some reason it took about 2 hours from start to finish.

As an aside, it is worth mentioning that I bought the rear subframe mounting bolts as a kit, so everything was just there ready to use.

Now with the subframe in place, I was able to attach the shock absorbers. Supporting the radius arm, I cut the string and attached the lower part of the shock to the radius arm. With a little wiggling, the top part fitted through the hole in the top of wheel arch. Then inside the boot, to attach the top bush and bolt. I decided to use the shocks that were taken off. All I did was give them a lick of paint to make them look better. Maybe someday, I will get better ones, but not as part of this project.

Attach the handbrake
I decided to replace both parts of the handbrake cable. The compensator bracket is the original one that has been restored. One thing I am glad of is that I kept all the parts of the old handbrake as the new one does not come with the clevis pins needed to attach to the backplate lever.

My hand brake was pre-assembled some time beforehand and written about in this post. So because of this prior work, fitting the handbrake turned out to be pretty easy. I just threaded the ends of the cable through the corresponding holes in the subframe, over the pre-greased handbrake quadrants and onto the levers in the backplates. This is where I needed to use my old clevis pin and split pin. Having done both sides, I seated it into its guide on the subframe, again with a generous helping of grease and threaded the top end through he hole in the floor so it could be attached to the handbrake lever inside the car.

Inside the car, I reassembled the end of the cable back onto the lever and attached everything to where it came from. Pretty much the reverse of what I did in item 2 in this post here

Then outside again to hook the springy ends into place on the backplate brackets as shown below.

I left the handbrake loose for now until I had the brakes set up correctly.

Speaking of brakes...

Bleed and set the brakes
Having heard from other people how difficult it is to bleed brakes alone, I did myself a favor and bought an EEZIBLEED kit. This made the whole job so simple.

But before any of that could take place, I needed to re-connect the brake line below.

With the brake lines all together, the instructions in the kit are pretty straight forward. Basically, you use the pressure from a spare wheel to push new brake fluid into the system. The new brake fluid is poured into the bottle supplied, out of which come two pipes. One goes to the spare wheel and the other attached to your brake reservoir with a replacement cap.

Then it is just a case of visiting each of the brake bleed valves and opening them and allowing the pressure to push the new fluid through.

So glad I bought this kit as it make a potentially difficulty, very easy. I gave a few pumps of the brake peddle also to make sure all the bubbles were out. Then once the drums were on,  I was able to use the brake adjuster on the backplates to set the brakes up and fine tune them.

Install the petrol tank
By now I am getting a bit tired, but I only have one day to get all the jobs done. So onward to the petrol tank. While this was out, I gave it a new coat of paint to tidy it up a bit, so I was extra careful putting it back in so I didn't scratch it.

Placing the tank back in the boot, I reattached the petrol hose and overflow pipe. Also I bolted in the top part of the strap. Next was to seat the new inner foam sealing ring over the neck.

Then, pushing the tank into position, the neck goes through the hole in the car body. I loosely secured the lower end of the strap so I had some wiggle space. Now the difficult part. Using a little washing up liquid on the inside of the new rubber outer sealing ring, I slid it onto the neck and into place. Then with a screw driver and a great deal of care, I pushed the rubber through the hole and eventually the whole thing into place.

Finally I used a wooden peg and hammer to and tapped the rubber to make sure it was in place. The last thing was to make sure the lower bolt in the strap was secure.

Attach the exhaust
By now, I am really knackered and it is raining, but the exhaust needs to be put on and put on carefully as I have wire brushed the rust off and sprayed it with high temperature paint. I was going to change it for an RC40, but the budget would not stretch that far at the moment.

So, now that I have spent all that time and energy making the exhaust look nice, I didn't really want to make a mess of it when re-installing the thing. So I wrapped it up with an old sheet while I slid it under the car.

Having never fitted an exhaust before, I knew it would be tricky, especially as I had dropped my inspection light and smashed the bulb! So it is cold, dark, raining and I am down to a small torch for light. Suddenly the joys of Mini ownership seemed a little less joyful! But I must press on.

The method I used to fit the exhaust was to slid it under the car from the rear and try to find the gap near the gearbox. Once it was roughly where I wanted it, I loosely attached the rear and middle mounts leaving plenty of wiggle space.

Now the tricky bit, attaching the end of the pipe to the manifold. There is a clamp that holds it in place and it is quite a tricky job to hold the exhaust in place and get the clamp on as you need 3 hands. Plus the added complication of the sealing paste makes it even harder. To solve the 3 handed dilemma, I used some string and tied to the front bracket of the exhaust. This allowed me to pull the exhaust up onto the manifold from the engine bay. Once it was where I wanted, I tied the end of the string to a bolt on the rocker cover. This allowed me to concentrate on getting the paste and bracket in place. Of course the whole job would have been made easier if I had removed the carb, but I was in a rush.

Despite the carb being in place, I managed to get the clamp in on and tightened up with two spanners. Then it was under the car to attach the clamp to the gearbox and to fully secure the middle and end clamps.

With all that done, I put the battery back in and connected it up and held my breath while I tried to turn the engine over. There was a moment of delay where I suspect the petrol was being pumped through, but it started and sounded like it always did. Phew.

I decided to gingerly take it for a test drive up the road and back again and all seemed well, except for the front subframe mounts. But that's a problem for another day!! There is just a little tinkering needed to get the brakes properly setup and the ride height to my preference, but apart from that, I am well chuffed with the days work, even if it did take 11 hours!

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  1. You might want to put the brake shoes on right. The un-lined part of the shoe goes at the top of the front (leading) position. http://www.widman.biz/mini_pics/m16/suspension_assembled.jpg

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  3. Thank you, you have a keen eye and it took me some time to notice this issue which I eventually covered in this post.