Digsy

Its official. I was talking out of my a*se. Although there is a slight improvement in cooling with increased concentrations, the concentration for hot countries is much lower (20/80). Sorry for the mis-information.

I think it works both ways. The more concentrated the coolant, the better it should perform in hot climates too. Its actually that I was thinking of when I was typing. I have been working on an engine for a hot climate recently. I'll double check that its the case tomorrow.

With our climate and without any other information I would go 50/50 or 40/60 if I was feeling tight that day. Doesn't the good (hand)book suggest a ratio? Pre mixed coolant? Hmmm. That's right up there with pre-grated cheese!! :-)

Ash. Is it a liquid "gasket"? Do you know if it is anaerobic or RTV? If it is RTV there might be a simple (if slightly bodgy) way out. If it isn't RTV then you can fast forward through the next bit. RTV means room temperature vulcanizing - a posh way of saying it cures without the need for baking. Bathroom sealant is a type of RTV. A properly designed RTV joint comprises of the sealant that fills up the microscopic gaps betwen the two mating surfaces, and a retained bead that usually sits either in a groove in one of the surfaces, or a chamfer on the inside or outside of the joint. Sometimes, and only very rarely, an additional backup is required, for example: If the width of the mating surfaces is narrow, or you cannot package a bead chamfer (i.e. around a fastener hole), or if you are trying to seal a "T" joint, where three components are coming together in one place. In these cases an additional bead of sealant can be squrted onto the outside of the joint. Yes, it sounds like a total cobble up, but I have recently had dealings with Threebond regarding the design of just this type of seal and this was one of their proposals (not one that was taken through to production I hasten to add). If the leak is minor, and the site can be cleaned up *very* thoroughly, you *might* be able to get away with applying a sealant bead to the outside of the joint. One final thing. For God's sake don't use a silicon-based sealant. Get some proper stuff from either Threebond or Loctite. If you can get in touch with them directly tell them the application and ask for something catalyst-freindly. It might be worth getting the proper surface cleaner / activator from them too. I have their numbers at work. I'll dig them out tomorrow if you think its worth following up.

No problem. So do you!

Mycroft, I have just been furnished with a load of information about our coolant recirc. pumps. Far too much to post in here. I have two alternative pump designs, together with engineering drawings and techincal specs. Slight problem: The specs are all in German. My e-mail address is on my profile. If you send me a mail I'll reply to it with the stuff attached, if you like.

Brilliant, guys. Thats cool. Now I *know* which bolts you are referring to. :-) Somehow I didn't think it would all sound so easy if you had to undo the 118Nm "Jesus bolts"! Thanks again, guys.

Cheers Alex / Martin. Just trying to finalise which bolt we are talking about: 1) If the one you have to remove is one of the caliper to upright bolts I would expect that you also have to loosen the top one? Correct or not? 2) The correct torque for this bolt is 118Nm (from MKIV.com) which is slightly tighter than a wheel nut (103Nm). Did it "feel" about the same when you undid it? 3) Or maybe its one of the sliding pins you remove, in which case the torques would probaly be lower. Oh I wish I had payed more attention when I had my wheels off! :-)

I am going to replace all my pads soon on account of their lack of thickness. Looking at the how-to pages on MKIV.com, it shows the pads being installed from rear without taking the calipers off the upright. However, the caliper design is plainly different so I'm assuming that this is the UK / US spec (or "proper") brake design. Looking at my J-spec calipers I'm pretty certain you have to take the caliper off the upright and install the new pads from the "front". Is this correct, and does anyone know the correct torque setting for the J-spec caliper bolts, and do they need replacing too?

Hi Tony. I took one of my headlights out last week. It was held in by 1x bolt (on the inside edge visible from the top of the car, and 2x nuts, accessible from the rear without removing anything. There were also two locating cones, one on each side. I *think* I had all the necessary fixings, and (to quote Ashford & Simpson mine is "solid, solid as a rock".

Maybe worth checking with this person to make sure they are not getting confused with the release bearing. A thrust bearing is a (usually) planar "white metal" bearing which reacts end-loads on a shaft. I don't know if the input shaft on the Supra gearbox is loaded in this way. I wonder if Martin has a cross-section through the gearbox? Helical gears produce endloads when they are driving, but I'm not sure if this would happen in neutral or not. The gears would be meshed but they wouldn't be transmissing torque (if they were turning at all) so any thrust they generate would be tiny. Failing that, always drive your car near a Toyota garage!

I don't know precisely what was used, but I would assume it was a dedicated water unit. I am on holiday this week, so I will try to find out more details when I go back to work. Point taken about the oil deposits.

Are the turbos on the Supra / Soarer engine oil cooled only? We have used electronically timed *water* recirc pumps before on Garrett T25s. I think its a fairly simple part that can be plugged into the cooling system. A simple timer which senses the ignition switching off could control it.

Cheers, Phil / Eyefi.

Phil, Any idea of the thickness when the noisemaker contacts the disc? I want to pre-empt this a bit in case the J-spec pads take a few days to source.

That's interesting. At my last service, all my brake pads were marked as "not requiring attention before the next service". The next service is still a month away, and they clearly *do* require attention.

What with the car up on stands this fine week (when I should be cruising about in it and generally enjoying my holiday) I was doing some pre-Hammerite wirebrushing on my rear wheel hubs today, and I uncovered some writing around their outer edges. MIN TH 15MM MAX DIA 191MM Obviously describing the limit dimensions for something brake-related. Anyone know what? The brake disc itself?

Hi all. Does anyone have an opinion on the minimum pad thickness before changing? My rears are down to about 1/8" (good old Imperial units), and the front are at about 1/4". Definitely going to change the rears ASAP because they look a bit dodgy (no squeals or warning lights yet though). Your opinions would be valued re: the fronts.

Ok Gareth, I walked into that one! :-) (Actually I didn't know if he meant the plugs were completely sh*gged out, or they just looked dodgy upon removal). Catalysts don't like misfire. I think it has something to do with unburnt fuel entering the exhaust system. It may only apply to close-coupled catalysts which are near to the exhaust manifold. I'll have a chat to some of our development guys to find out how tolerant they are. Apart from cats, misfire (in excess - lots of cylinders for a long time) will "wash" the cylinder bores with fuel, causing accellerated wear, and if any fuel gets beyond the piston rings you can get a degree of oil dillution.

Have you been misfiring?

Whoooph! I need a wider screen! :-) Thanks for that Martin. My money is still on it being the input shaft bearings or the release bearing. If the DMF is worn I think you would also notice something on acceleration / deceleration when the torque between the two plates reveresed. One more note for Martin: If you do e-mail me anything, please can you keep the attachements below 1.5Mb? My Yahoo address will reject anything larger. Ta!

Hi Martin. Thanks! My e-mail address is on my profile. I was looking around what is left of MKIV.com the other day. They used to have a complete technical description of the Supra engine there which made interesting reading. I don't suppose you have this too?

When the car is in neutral with the clutch out the only parts of the gearbox assembly that is turning will be the clutch assembly and input shaft. The clutch driven plate will be locked to the flywheel so nothing should be rattling there. The clutch release bearing will be "free" because you are not loading it up by declutching. When you put the clutch in you decouple the driven plate and input shaft from the engine and (theoretically) it should all stop turning. There will always be a little bit of drag from the clutch plate so won't stop completely. The release bearing will be loaded. It sounds like either a worn input shaft bearing or a worn clutch release bearing. My BMW had the former problem for the three years I owned it and it never gave any real problems. It was annoying though. It was a known problem with the gearbox so the mechanics at the local BMW dealership put my mind at rest as soon as they heard it. If it was a flywheel problem I would have though you would feel more wheh the clutch was in rather than the other way around, because when you declutch you are effectively reducing the total system inertia and therefore increasing the vibration in the cranktrain. However I don't have much direct experience with dual mass flywheels so I don't know how they mate to the clutch. Martin, do you have a schematic of the Supra DM flywheel I could see? Purely out of personal interest. Synchros are only working when you are move between gears. In neutral no gears will be dogged to the output shaft, so I wouldn't have thought it was a synchro problem. If the cones were worn enough to rattle you may have noticed a degradation in shift quality as well, but you didn't mention that. HTH.

Brian Duff has painted Angie's lower lip. Looked nice too. Next time he pops in I'm sure he will tell you all about it.

I always brim my tank and since I bought my car I have got an average of 57.86 litres in each time. God... Maybe I should get a life!