All Four Brakes Locked And Binding Badly

[Eddie]

This was me at the weekend went to put my foot down and My '93 ls 400 went nowhere. and basically started braking by itself, so I came to a slow stop. I called Lexus and they told me my master Cylinder was dodgy, and needed replacing. so does any one know where I can get one apart from a lexus dealership, I've just paid out £800 for a service and new tyres need to get this and fitting as cheap as poss!!!!

Your assitance would be much appreciated..

Cheers Eddie

[L3X JG]

Try and find a scrappy there are a few about my brother in law just replaced his on his Gs it came from a scrappy, It's not hard and does not take more than about 3hours.

[randyreindeer]

I had the same problem on my old Celica many years ago. It was caused by the servo sticking and not the master cylinder. Maybe worthwile getting the servo checked as well

[lexicon]

I'd agree it's more likely to be the servo than the master cylinder.

[eXOBeX]

Exactly the same thing happened on my 1995 GS last weekend, and once more this afternoon.

The pedal goes rock-solid and the front brakes bind up, as though there's too much fluid in the system! Once left to cool down for a while, it was fine and acting as though nothing had happened!

Can the servo or master cylinder be repaired, or is it scrapyard time? Any suggestions for telling which of the two is at fault? I don't know about the back wheels, but both front ones had locked indicating that both brake circuits were affected. Looking about on the 'net I see that dual-circuit brakes have effectively two brake cylinders in one, so as I write this the servo is starting to look like the culprit...?

Then again, immediately below the master cylinder the servo's paint has bubbled, indicating that something's leaked fluid onto it (or someone's overfilled it!).

Also, the front brake pistons aren't easy to shift. Squash one, the other pops out, fair enough. But to squash them both, I have to use a vice!

UPDATE

Brake servo complete with master cylinder, just ordered from Foreign Car Spares of Birmingham. £175+£10 carriage, plus VAT. Had a quote about 15 minutes later for £150+VAT though, then another for £100 - typical!

Don't try importing the servo from the US or Europe, the servo part number for GS300 Mk1 is 44610-3A030 for RHD but 44610-3A040 for LHD. Master cylinder in both cases is 04493-30240, also found in the NATO version of the Supra from July 96 onwards.

Will be fitting it myself, following the instructions in my Haynes manual (unfortunately a Carina one, but close enough). Step-by-step guide with piccies may well appear on my website soon afterwards. Will also do a post-mortem on the old servo and cylinder to see what had happened (again, with piccies on the web).

FURTHER UPDATE

Changed master cylinder only (servo looks too much of a potch so tried half the job first). Bled the brakes (if you buy an Eezi-Bleed don't forget to buy the Universal Cap too). Job done, no more binding. Stamping on the brake pedal used to jam the brakes, doesn't any more!

Seems to be a bit of play in the pedal which comes and goes, so I think the servo might still be iffy, it's just that the play takes up whatever expansion there is (there was no play before, so the expansion simply applied the brakes!)