Saturday, August 29, 2015

Brake Cylinder and Limiter Valve - Demuckification

In the previous post, I declared (tongue in cheek a little) that I was starting 'Operation Tidy the Engine Bay' and started off by removing and overhauling the two clutch cylinders. Now it's the turn for the brake cylinder and the limiter valve as they look like they have seen better days.

Due to the complication of these parts, I decided not to take them to pieces at this time, preferring to just clean them up and make them more presentable. Hence the reason for titling this post as a 'Demuckification' rather than an 'Overhaul'.

Brake Master Cylinder and Limiter Valve

Limiter Removal
To remove the brake limiter from the car, all four pipes that go into the top and bottom of the unit were undone and disconnected. I used a cloth to catch the escaping hydraulic fluid as it inevitably leaked out.

Once that was done, there's a single bolt that secures the limiter to the bulkhead which needs to be undone. Thankfully it's on a captive nut, or else you would need to be Mr Tickle to reach both the nut and the bolt at the same time! Once the limiter was removed, I used the fingers from some rubber gloves to cover the ends of the pipes to stop any bits getting in.

Cylinder Removal
Just like the master clutch cylinder in the previous post, getting the brake master cylinder out is something of a challenge. The two nuts that hold it to the bulkhead are easy peasy and offer no trouble at all, the real problem is detaching the bottom of the cylinder from the brake pedal.

The end of the cylinder, the bit you can't see from the engine bay that is, is attached to the pedal with a clevis pin which is secured in place with a tiny split pin. Normally this kind of thing would be no trouble at all, however it's located in one of the most inaccessible parts of the car, right up behind the pedals and pipes and wires!! To be honest, just seeing it, let along reaching it is something of a challenge!!

So how on earth do I get my hands in there to get the pin out, bearing in mind that I'll be holding a pair of pliers at the time and I won't be able to see what I'm snipping as my hand will be in the way. Hmmm, it's a tricky one!!!

In the previous post where I was faced with exactly the same problem with the clutch pedal, I found it easier to remove the large air inlet duct, the seat and the heater. I know, it's a bit overkill for one tiny clevis pin, but it really helped. I found that the heater didn't actually need to be un-plumbed as the water hoses were flexible enough to just move the heater out of the way.

With all these parts now moved, and the clutch peddel held down with a brick, it was just possible to get in there with a pair of pliers and snip the end off the tiny split pin and push it through the hole in clevis pin. Then the clevis pin could be pushed out, releasing the end of the master brake cylinder allowing it to be finally lifted from the car.

I honestly have no idea if it would've been possible had the clutch pedal was still attached!! I hope I never have to find out!

Now that both parts are safely on the bench, the rest of the brake pipes were removed and the usual cleanup with a wire brush and a drill removed all the crud from the outside. As I didn't plan to take this to bits, I stuffed up the holes with some rolled up masking tape to stop the muck getting in.

Once it was suitably scrubbed of it's filth and cleaned up with methylated spirit, it was given a few light coats of chrome effect paint to really make it shine.

During the cleanup process, the small grommet that covers the hole in the cap broke off. I did however managed to retrieve the bit that fell inside by pulling it back through the hole with a screw. Speaking to friends on facebook, it appears to be nothing more than a dust cap designed to keep general debris out of the valve. If that's the case, why the heck did they make it with a hole in, in the first place!!!

Anyway, I'm going to see if I can find a new grommet on the internet, failing that I'll use the old grommet with some RTV to hold it in place.

Master Cylinder
Moving onto the master cylinder, I could see no easy way of separating the plastic resovoir from the cylinder body. As I didn't want to force it apart and risk breaking it, I decided to clean it up with it attached. Using a wire brush and a drill, I cleaned the outside walls of the cylinder where I could, taking great care not to damage the plastic. For more tricky areas, I used a hand held wire brush and a little carb cleaner.

Once I was happy with the metal, I turned my attention to the grubby state of the plastic. I found that carb cleaner was very effective for dissolving all the black crud from the surface of the plastic and used in conjunction with an old toothbrush it did a very good job. They worked well together and no damage was caused to the surface of the plastic.

When everything was cleaned and rubbed down with methylated spirit, I masked off the plastic parts of the unit in order to spray the metal part. Due to the tricky shape, it took quite a while, but I took my time as wanted to make sure it was a good job with no overspray. To add to the task, I also had to mask off the yellow identifier tag as it wouldn't come off.

After a few coats of the chrome paint, the cylinder was transformed into something that looked reasonably decent!!

So that's another two parts ready and waiting to go back into the car once the engine bay has been sorted out. Well it seams that 'Operation Tidy the Engine Bay' is rapidly turning into quite a major little project, more than I expected really.

A lot more than I expected in fact, I could see various parts of the bulkhead that really needed some work doing but there was just no way to get to them as the subframe was in the way. So after a bit of 'umming and arring' and some 'shall I or shan't I' type thoughts, there was nothing else for it; the front subframe simply has to come out!! How else can I do a proper job! I'll just have to keep telling myself it's a good idea and just hope that all the extra work will be worth it.

<This Post> - 'Brake Cylinder and Limiter Valve - Demuckification'
<Previous Post> - 'Clutch Cylinders -  Overhaul'

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