Rover P6 rear brakes - special tool or not?

If you mean the Girling tool for winding the automatic adjuster back into the piston, it's not necessary. IIRC it's easier to remove the caliper and wind it in by hand. I have the tool, and found it slow and frustrating to use. Keeps slipping off etc. Mike.

Just what I wanted to hear. Thanks Mike.

Not a statement you'd want taken out of context!

No - you can do it with your fingers. They'll bleed for some time afterwards... Thin leather gloves etc can help.

Slacken the rear final drive mounting nuts down to the ends of the thread

- that will give adequate clearance to get at them. Clean the 'piston' thoroughly before attempting to wind back in - remember it's a mechanical device at this point not hydraulic so can be lubricated sparingly with ordinary oil. If they are really stiff remove the calipers, dismantle and clean up/lubricate the mechanism. In good condition it is one of the best handbrakes fitted to any car ever.

I'm used to that.

That's handy, I need to replace one of the mounting bushes anyway, so can combine both jobs. Thanks for the tip.

Indeed. As is probably all too common, the pads have worn right down so I'm expecting the pistons to put up a fight. As I'm replacing the front callipers and will be bleeding the system, removing the rears to clean up on the bench won't be any great hardship.

I thought I may as well switch to silicone brake fluid too while I'm at it. You haven't heard anything about P6s disliking it have you? It's worked well in my Triumph for quite a few years.

;-)

Can you now get them? It was one reason I got rid of mine in the mid '80s

- the various Metalistic mountings were like hen's teeth. Think I paid 50 quid for one.

In which case winding them back will be easy. Although the caliper pivots can fight a bit when trying to remove them. I hope you have a WS manual - the handbrake mechanism inside the caliper is a bit complicated to understand. Or was to me.

Hmm. I've often heard bad things about it. If you change ordinary fluid regularly - every two years or so - you'll not have rusting problems anyway.

Yes. Easier to use if the whole car was up on a ramp or you have a decent pit. Tricky lying underneath. If it had a proper ratchet it would be easier - pulling the lever out to move it round a notch pulls off the tool. As it were, missus.

They're all available from Wadham's, but aren't cheap. That particular bush was 20 quid + VAT and isn't genuine Metalastic. That, I believe is the problem, so folk are switching to polyurethane bushes to get around quality issues. They do turn up occasionally on eBay, where the same people always seem to end up bidding against each other.

Hmm, I've only got a Haynes. Better make sure I photograph it all as it comes apart.

So have I. But I've also used it without any problems so aren't too bothered by general mutterings. However if someone's specifically had trouble with a P6's servo and silicone fluid, for example, I'd certainly take notice. One point is that I changed all the Triumph's hoses and seals before switching fluids, and I've heard that rubber that's been in contact with DOT4 for a while doesn't take well to silicone. I'll only be replacing the caliper and master cylinder seals on this one, which could be a risk.

Perhaps you don't remember where the bleed nipple is on the rear brakes. Believe me, it's not somewhere I want to go on a regular basis!

My PI was bought with DOT5 in and I have kept it like that. But I wouldn't have bothered to make the change myself. And if you ever have a garage do anything with the brakes, it is essential that you gave a big *DOT5 Only* notice on your fluid reservoir. Because if DOT4 and DOT5 ever get mixed in the same system it is a flush everything, replace everything nightmare.

I have also heard that changing from DOT4 to DOT5 (or vice versa) without changing *all* the seals and rubbers (Master cylinder too!) is a recipe for premature failure. Unless you are going to be doing lots of crash stops from high speed and need the higher spec fluid, it is probably more trouble than it is worth to change.

Jim

It shouldn't be though, should it? I understood that one of the specs of the DOT rating was that they had to be capable of being used together safely. Obviously I'm not advocating mixing them as that removes all the benefits of DOT5.

Yes, I'd heard too. Perhaps I'd best give a miss this time.

Erm, sorry to disagree again, but I'd have said those circumstances were exactly when you _don't_ want DOT5's extra sponginess.

It says DON'T DO IT in big letters on my DOT5 top up bottle. I would guess that they say that for a reason. Perhaps the mixable DOTs end at

Not sure. You get the benefit of no water content, so no steam bubbles when everything glows red. And you don't actually want to lock the wheels (ABS and all that) at high speed so a little bit of sponginess is helpful. Having said that, the fraction of a second delay between stamping on the pedal in an emergency and feeling the full braking is a touch unnerving. Every time. I have had DOT5 in the PI for 5 years now, and I still haven't got used to it. Perhaps I don't do enough emergency stops :-)

Jim

I have a genuine Rover w/shop manual for the P6. Was intending to put it on eBay, but if you're interested make me a fair offer and it's yours. No idea of postage costs, but it would go about 5Kg inc packaging. Email me if interested. Mike.

Whoops! Make that 5 Lbs. Thanks. Any idea of a fair price. Softcover is a little grubby and discoloured but inside the pages are perfect. Mike.

The message from "Mike G" contains these words:

Still a great weight. I wonder if the Haynes manual is closer to 5 oz. :-)

My genuine Range Rover manual, a single volume from the early 80s, weighs in at a mere 2.5 lbs but the series 2 Land Rover set I used to have ran, IIRC, to 5 volumes and could easily have exceeded 5 lbs.

Probably because of the paper quality. Although the pages are not particularly thick, they do seem to be very dense, with a fairly smooth finish. It's also about 40mm thick. Mike.

I am, so have done.

The packaging on Automec DOT5 fluid says their's is safe to mix, but I do recall them including warning labels to fit to the reservoir telling you not to. That's probably just a reminder, to stop garages topping it up with normal brake fluid. I can't see that it'd matter if the two fluids remained seperate as the hydraulic effect would still work, innit.

But the garage normal brake fluid is DOT4, so it clearly isn't a good idea to mix them.

Theoretically yes. But I wonder how long the master cylinder seals will last?

jim

I googled and found this: DOT 5 Brake Fluid By Mike Burdick A while back when this topic came up, I posted excerpts from a Skinned Knuckles article on silicone brake fluid. They made the best attempt I've seen so far to actually address this issue with hard data instead of anecdotes. The data they used came from military tests in jungle conditions and tests from the original producer of DOT5 fluid (DuPont? I can't remember...). Even so, they were not able to come up with many conclusions about DOT5 fluid. In a nutshell, the conclusions were:

1. DOT5 does not absorb water and may be useful where water absorption is a problem.
2. DOT5 does NOT mix with DOT3 or DOT4. They also maintain that all reported problems with DOT5 are probably due to some degree of mixing with other fluid types. They said the proper way to convert to DOT5 is to totally rebuild the hydraulic system.
3. Reports of DOT5 causing premature failure of rubber brake parts were more common with early DOT5 formulations. This is thought to be due to improper addition of swelling agents and has been fixed in recent formulations.
4. DOT5 is compatible with all rubber formulations and it does NOT eat paint! They also made some general recommendations based on this data and personal experiences. These, along with recommendations of list members included:
5. If it works for you, use it. You won't hurt anything if you do the conversion correctly. (See, #2 above)
6. Careful bleeding is required to get all of the air out of the system. Small bubbles can form in the fluid that will form large bubbles over time. It may be necessary to do a series of bleeds.
7. DOT5 is probably not the thing to use in your race car although it is rated to stand up to the heat generated during racing conditions. The reason for this recommendation is the difficult bleeding mentioned above.
8. DOT5 is a good choice for the weekend driver/show car. It doesn't absorb water and it doesn't eat paint. One caveat is that because it doesn't absorb water, water that gets in the system will tend to collect at low points. In this scenario, it would actually be promoting corrosion! Annual flushing might be a good idea.

Jim