So on sunday morning, i braked quite heavily. all was good, passed it off. Now the next time I braked, it was like there was nothing in the pedal, i had to push it almost all the way in till i got some brake response. for a bit after this it felt a bit sloppy, but eventually went back to normal and i continued driving.

Today driving along i went to brake when suddenly there was nothing in the pedal again, i had to push it right to the floor and then locked up the wheels and gave it a little skid. it continued being sloppy till i pulled into a side street and called the RAC. after waiting an hour and a half for RAC, he was inconclusive about what had happened, apart from saying it felt a little loose towards the bottom (by this point it felt normal for me) and that i should tighten my handbrake too. he said the cause could be (sorry forgot terminology) in the box bit inside the engine bay that the brake pedal goes to, with a broken valve, allowing the fluid to transfer between the 2 sections. he also said it could be something to do with warped disks, or having cheap pads put on which instead of grinding down the disk, doesn't grip and just slides like metal and wood.

he said i'd have to take it to a mechanic, and get them to probably bleed it out and give it all a full check.

anyone with experience, thoughts or theories on the matter? i can imagine getting a full check done being expensive which i dont have the funds for at the moment, so any help is greatly appreciated.

cheers guys

Bleed the brakes, New Brake fluid. if it still continues i would be looking at the brake booster

Not the booster. In your brake master cylinder are several rubber seals. With age the lip on these wear off and the brake fluid leaks past them. Often you dont notice the slight leakage that it begins with till as you found a heavy brake application sends em bye bye. Repair kit is available from any good brake repair specialist. Did mine 6 mths ago cost me 50.00 for the kit. Will only get worse until finally no brakes at all.

Not the booster. In your brake master cylinder are several rubber seals. With age the lip on these wear off and the brake fluid leaks past them. Often you dont notice the slight leakage that it begins with till as you found a heavy brake application sends em bye bye. Repair kit is available from any good brake repair specialist. Did mine 6 mths ago cost me 50.00 for the kit. Will only get worse until finally no brakes at all.

this would be the thing just past the firewall which a rod pushes into and has 2 sections? that he would have been saying goes to front L/back R and vice versa?

awesome cheers mate, so basically go to a brake repairs place, and they should be able to do it easy? i have no mechanical understanding or ability.

it got that bad? I remember you saying you got some play, I've got play which I'm getting used to, I blame it on $35 brake pads...

I had a similar problem which resulted in me getting a new brake master cylinder for the awesome price of $600

3 days before getting my new TL :(

Find a brake specialist who is prepared to strip down and replace all the worn bits in the master cylinder, rather than just junking it and replacing the whole thing. Big difference in price. The kits are cheap and labour is less than an hour. As a DIY exercise it is easy and cheap to do.

Easy to identify too, pump the pedal until you have pressure (engine running), then keep your foot on the brake. If it sinks slowly then the rubbers in the master cylinder need replacing. Worth doing once in a while as a check, because they can go from GOOD to WTF HAPPENED TO MY BRAKES? very quickly.

Needless to say, you have checked for adequate fluid level in the reservoir and leaks at the calipers and hoses?

Ferox
Master cylinder is attached to the brake booster (round black thingy) on drivers side of firewall. Has metal hoses running out of it.As MadMax said you can go from good brakes to OH F*** in an instant. Only need for master cylinder to be replaced would be if the bore inside where the piston and rubbers go is scored or otherwise damaged if it is you will need to replace it.

Good idea when replacing seals in the master (or slave cylinder for that matter) is to get it honed as brake fluid absorbs water and causes the bore to rust chewing seals out. I've found as well when there is a pressure difference in the master cylinder, hose split, seals etc the brake fail light comes on but usually after you have depressed the brake pedal and have realised for yourself that the brakes have gone to s*^t.

cheers guys, great help. yes have checked levels and all fine, no leak. will take it to a brake specialist. if it comes to replacing the whole cylinder, i'll probably get rid of the car. not worth 600 for a car worth maybe 3 times that.

So why not the booster, what about the reaction pad, this could be the issue, especially if the master has been leaking back into the booster

I dont believe in reco master cyl, by the time you re sleave, re kit and hope that the person doing it knows what they are doing, you will end up costing yourself a similar amount to a new one

I can not see why a new one would be $600, you may be able to find a wreck with a newish master cyl, I know that the self serve wreckers here I have often seen them where they have clearly been replaced at some stage.

Easy to identify too, pump the pedal until you have pressure (engine running), then keep your foot on the brake. If it sinks slowly then the rubbers in the master cylinder need replacing.

Sorry to hijack but I just tried this, and my pedal does sink to the floor after being pumped. Is it safe to say my master cylinder is stuffed? Or can something else be causing it? Car in question is 03 KJ with 165k.

If it sinks all the way to the floor but regains normal height when you pump it a few times, yes, I would say you have a problem. Get someone to look in the reservoir with the cap off and repeat, if you(they) see turbulence in the fluid as the pedal sinks then the fluid is flowing back into the reservoir past the rubbers.

Have the engine running when you do all this, so the booster can apply normal pressure.

PS If you apply the brakes with the engine off, and then start it, the pedal will sink considerably. This is normal booster operation and nothing to worry about.

To Mal: Mitsu doesn't recommend honing or resleeving their brake cylinders. They are made from aluminium alloy and not prone to scoring or pitting, unlike the iron ones found on other cars. If I bought one from the wreckers, no matter how fresh it looks, I would still dismantle/rekit it, and check the bore, so I might as well do my own when the time comes.

Sorry to hijack but I just tried this, and my pedal does sink to the floor after being pumped. Is it safe to say my master cylinder is stuffed? Or can something else be causing it? Car in question is 03 KJ with 165k.

Check the power booster paintwork for blistering, peeling directly underneath where the master cylinder bolts up. Blistering & peeling paint is caused by brake fluid leaking from the master cylinder rear seal.

Cheers

I was slightly over I paid roughly $320 for the cylinder (no idea if that was reasonable or not) and about $150 for labour.. there was a bit extra on it which was rear brake pads.

Unfortunately because he was closer and my usual guy was busy I took it to my dads mechanic and he just went ahead and did the lot without even letting me know (despite asking).. so I have no idea if that's a good rate or not.. oh well.. Sorry to scare you!

Sounds about right for the parts and labour costs. Remember most mechanics want to fix the car quickly and properly, so they chuck on a new one and bleed the brakes, then bin the original without looking if it is still serviceable. If you have the time and knowledge to DIY it is much cheaper, but if a new kit doesn't do the trick, then you end up spending more time on the job.


lol Just took my own advice, and the pedal sank slowly and the ABS light came on. Went to u-pull-it for another master cylinder, but no luck. Plenty of TR/TS 4 cylinder master cylinders, and some V6 ones, but not one of the TS V6 ABS master cylinders to be found. Strip and re-kit time, I think. A good time to pop the pistons out of the calipers and clean out 15 years of accumulated rubber debris and lube the guide pins, as well as checking disks and pad wear. This way the brakes work smoothly and the fluid in the reservoir stays clear for years to come, just like a new car! Must get the kit first though. Brakes work normally, or appear to be adequate at the moment.

Must remember to take pics on this job and post them up.

forgot to mention, non-abs if that means anything.

Just means its cheaper and easier to get an overhaul kit or a new master cylinder. For the V6 TS wagon with ABS the overhaul kit is unavailable, and a new master cylinder is $250.