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Triumph TR6 - brake conversion -Toyota??

Hi all - my 1st post - just found the site and spent 4 hrs of work time enthralled.
I'd appreciate some feedback on the Toyota front brake conversion. What do you use?, problems and concerns etc.
I read the thread 'Big Brake' but the Toyota donor vehicle was not mentioned.
I'm considering doing a Volvo 4 pot caliper conversion (using the existing discs) and an alternative would be good.
Also, 7/8" rear wheel cylinders - is this recommended for the bias or for hydraulic issues?
Lastly - is the existing booster (in good nick) OK to use?

Thanks
Roger H

Roger
Read Lee Janssen's TR6 website. Everything you need to know. He even shows brake tests after each brake mod.
Steve H

Thanks Steve

Very interesting - nice to see someone willing to share their hard work.
Roger H

The Toyota calipers are from a 1979 through 1983 four wheel drive pick up. They were also used on the early Toyota Four Runners (don't know what they might have called these in OZ or if they were imported there). The easy discriminator is "does it have a solid front axle or independent front suspension and are the rotors vented or not?" If it is the solid axle, non-vented rotor version, you're in business. There are two tricky bits in making the conversion up front. First, you must make some custom brake lines that are Imperial on one end and metric on the other. They must be formed in there rather tightly to make sure that you dont foul the front suspension on the TR4 through 6 being converted. The other is that you either need calipers bolts used with the M16P (late 1972 onward) Girling calipers or you must find or make (likliest scenario) bushings to allow use of the 16P or 16PB caliper mounting bolts. You must modify the dust shield to clear the larger Toyota caliper, nothing tricky, just a little cutting and deburring. You use the stock TR4-6 rotors, front hubs and caliper mounts.

At the rear, Girling number 64673804 rear wheel cylinder .875", fitted to MK I and II Sunbeam Alpine plus just about every four wheel Morgan can be fitted as a direct replacement for the TR4-6 rear wheel cylinder. No modification required, just take out your stock parts and replace with these. I installed the Toyota caliper and .875" rear wheel cylinder set up on my TR6 and found no problems in brake balance.

Below is a link to a write up from John Lye and Lee Janssen:

http://www.vtr.org/maintain/brake-conversion.html

SteveP

Cheers SteveP

'Four Runners' did make it here so I'll check it out. Preliminary checks showed that the 80 series Landcruiser are close to a match but they are big $$ if it's a current model.
Guys here seem to favour Volvo calipers which need some minimal machining and a 1/8 mounting spacer - they also use the existing discs as a starting point.

Lee Janssen's article on his test results suggests that there is only marginal improvement - not as much as I expected - and that a rear upgrade with 'good' pads on the front may be not far off the alternative 4 pot conversion. Trying to read between the lines, his results for the 4 pots got better (than stock) as the tests progressed - maybe this was heat related and a quality difference in the pads? I'd appreciate your thoughts as to how noticeable was the upgrade on yours.

Anyhow, thanks for your feedback. I'm also looking at Range Rover calipers but info on these is heresay at this stage. I'll re-post if there's any earth-shattering outcomes!!
Roger H

Steve P.
Am just about to do the front Toyota caliper and
rear Alpine cylinder conversion. Did you find that the
upgraded braking distance was similar to what
John L and Lee J. reported?
Christopher Trace

Truth be known we have not done any measurements on stopping distances. The brakes do have a good feel to them and seem to haul it down in a hurry. Not too terribly long after doing the conversion we decided to strip the TR6 down and have it painted (see removal of stuck windscreen frame thread), so not a whole lot of seat time in it with the new set up. As for the improvements in John and Lee article, the big improvement was doing both front and rear changes. Doing front only the drop was from 262 ft with 19 ft sigma to 243 with 9 ft sigma. When the calipers were combined with the 7/8 wheel cylinders it went to 215 ft with 9 ft sigma. While I fully buy into the majority of the braking being done by the front end, the TR6 has so much weight in the back that the rears have more influence than for most cars out there.

Heat build up would have an effect and things would also be expected to improve somewhat as things became bedded in.
SteveP

This thread was discussed between 14/01/2003 and 24/01/2003

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