Poor Brake Performance

[snowman]

This thread is for ongoing discussion about any braking performance issues of the Tritons. I have kept it separate from the upgrade threads or issues such as flushing etc.

I have been concerned about the braking performance of my ML for a while now. After upgrading the front rotors and pads there was no significant difference in HEAVY braking performance. Again, like my transmission, this is a bit of an investigation thread and communicating some trial and error to see why i do not have good brake performance, when you really need it.

As i have the same issues with standard pad and rotors (for one off hard applications) i do not believe it is pad or rotor related.

My brake pedal and feel at light and medium application is seemingly identical to another car of the same type and brake upgrade. It brakes quite well in these circumstances but as an example at Lithgow in high range diff lock on (no ABS) i was unable to lock up the muddies on a wet dirt road. It still pulls up quite well but i believe that with no ABS and full pedal application it should be able to lock all four up in these conditions with no problems.

Hence i think i am not developing enough caliper clamping pressure.

I have rear braids.
I have had all the fluid replaced with good quality DOT4.
I have DBA slotted rotors and Bendix 4x4 pads.
I am getting front braids added next week.
I have not done a 'brake clean' yet (thanks BG) i will get this done during braid upgrade.
All the above has been completed by a brake specialist.

So i am hoping others may have had some similiar experiences and by sharing advice we can solve the problem.

Thanks.

[sam]

Sounds like you could have a prob with the master cylinder or the ABS controller mate as they are the
only 2 things that stand out as you've been through and upgraded front discs etc so seems as though
the pressure is being limited by one of these .

[salt36]

Correct me if i am wrong but trying to pull up a two tonne vehicle with two discs and two drums is a compromise at best.

Larger diameter discs (X4) and twin piston calipers would make a significant difference imo.

I share your concern Snowy and spending a lot of time driving around town there is situations where you need to be able to stop quickly....... I usually slow down when it gets busy so I know i will be able to stop in time.

Vehicles I have had in the past have been the same so I guess I am used to it.

[borngeek]

I have driven snowies vehicle and it is a lot different to mine in braking performance....

I can lock (activating ABS as I have no difflock) them all day long without pushing my feet to the floor.
I have the same brake upgrade exactly. I have flushed my fluid. I would have an emergency braking situation daily (Sydney city ). I have overheated my brakes for the hell of it on several occasions and good braking performance remains... I reguarly hit them with brake kleen as a maintenance tool.

This one is a mystery...

I would suggest master cylinder could be a issue like Sam has.. It is definately a safety issue but with the rotor and pad upgrade you recon a dealer would help??? I know snowie had the issue prior to rotor upgrade so it is definately something else at play here. I would force them to take a look personally and really kick up a stink it sucks he is paying a brake specialist really...

Maintenance wise brake cleaning spray available from all your usual spots is a great investment. It limits the amount of impure stuff building up that causes your pads to become glazed which significantly reduces braking performance. Glazed pads is very common and best way to fix this is to remove pads and hit them with a tough wire brush and refit. This enables you to 'rebed' the pads with the rotors. I suggest if you do this to find a nice private and quiet road and spend a lot of time jumping on and off the brakes at various load levels. Once finished and cool give them a good spray with the cleaning spray and then go enjoy the difference
This sounds crazy but isnt as crazy as you think but geting a hacksaw and putting small grooves across the face of the pad will help this rebed to occur and get a much better bite for your braking system. 4 or 5 evenly spaced will suffice. 1mm deep.

I did this kind of stuff on dirt bikes and karts routinely. Stopping a 250 or 500cc dirt bike at the end of a straight at 200k+ was important! We used solid, slotted, slotted and ventilated disks depending on the application and braking times. Short circuit required a lot of brakes, motox not so much...

Another massive consideration is pad compound. Soft pads bite much better and wear far quicker. Hard pads are durable but dont bite quite as nicely and take a bit more time to get to operating temperature where braking performance is optimum so in general they are not as good at braking as a softer, faster wearing brake pad. Personally I would rather go through 5 sets of pads over everyone elses 1 set if I needed to stop fast and consistent. I dont drive my car on a race track so durability is one of my considerations so I have gone with a harder pad and swallowed the fact that braking performance is slightly reduced as a side effect.

I be interested to hear how many owners who get a good 60--80km/h runup on the tar, or dirt for that matter, jump on the anchors (both feet if you want) and get the abs cranking... small little jerky locks...
I have a awful feeling that it is more common than just snowie... I couldnt do it in a MN i drove recent. My brakes are much much better than snowies ML and there is no reason as to why. The fact this particular MN couldnt do it, I initially blamed the 20 inch road wheels having too much grip.... That still could be the case but really brakes should be capable of locking (and having abs relieve them).

[steve1961]

Something amiss there for sure ... like B/G above ... i do lots of city driving and can "chirp up " the tyres in a heartbeat with a moderate jab of the foot
many years ago in a holden i had a similar problem and it was eventually traced to a scored piston in the master cylinder causing blow by

[Joe]

I have no problems with my brakes. I run DBA slotted rotors with Bendix pads and whilst the pedal is a little softer than standard (even after fluid flush), they pull up fine and I can activate the ABS quick easily.

Snowy, have you taken it in to get a proper brake analysis? I know that jop had his in for a check up and they found the brakes to be way off balance front to rear and side to side. Maybe you have mud caked in the rears or something.

[patto]

All factory with me and i find the brake performance quite good considering its weighs in over 2tonne. I can get the ABS working no problems.

[Steane]

No probs with my brakes. After the upgrade to the slotted discs they were a bit laclustre but came good with a bit of use and are now better than the original discs with oem tyres (now 32s). Activate the ABS no probs.

[ultimate]

I have no problems with my brakes. I run DBA slotted rotors with Bendix pads and whilst the pedal is a little softer than standard (even after fluid flush), they pull up fine and I can activate the ABS quick easily.

Snowy, have you taken it in to get a proper brake analysis? I know that jop had his in for a check up and they found the brakes to be way off balance front to rear and side to side. Maybe you have mud caked in the rears or something.

That's a good idea Joe. http://www.safetstop.com.au/safety_checks.html is the system that Jop had his tested on. The manufacturer is actually right behind our workshop and we know them pretty well. It's a great system and there's a few operators near your area snowie. McGraths is a Mitsubishi dealer but any of the other workshops will do the test for you no problem. It only takes a about 5mins and gives you a complete read out on your vehicle showing brake balance, weight and even alignment to some extent.

McGrath Mitsubishi Liverpool
Terry Shield Toyota in Parramatta
Trivetts BMW in Parramatta.

[snowman]

Snowy, have you taken it in to get a proper brake analysis? I know that jop had his in for a check up and they found the brakes to be way off balance front to rear and side to side. Maybe you have mud caked in the rears or something.

When i had all my wheel studs replaced the brake specialist also gave them all a good clean etc.....

many years ago in a holden i had a similar problem and it was eventually traced to a scored piston in the master cylinder causing blow by

I guess this is something i am looking for. i will get the brake guy to have really good look first and then if he still cannot find it i will get him to write a letter and go hand in hand to Mits to try and get the technology looked at in this regard. i can assure you i am completely at peace with using a specialised brake guy (and very decent approachable bloke) to look at it and make the braids first before i even waste my time going to Mits.

They will see the different pads and rotors (even thought we all know they are better product) and just not show the least bit of interest. i am over that.

Looks like i bought the friday afternoon special......... It is becoming a bity weary to be honest. if i didn't have 10k+ worth of extras then i would probably get rid of it at the end of the ease, but i don't know what i would replace it with. so i have to push on. i can see the light at the end and it is a nice bright light.......

[Homer]

Yeah Snowy you've got a problem mate.
I just immediately locked up (ABS kicked in and chirping) my D694's which are grippy as hell and nearly went through the screen...did it a second time 200 metres later and the same result. Slamming the foot on 'em is instant ABS and that was on dry sealed road.

I should add:

After some other comments I've made I must clarify I'm happy with my ultimate upgrade. The std Triton rotors are shit and warp and get hot spots if a "quick run" is done anywhere requiring multiple heavy braking or long downhill range type applications.

These rotors are absolutely fantastic. The pads (or mine are) are a harder compound than std so the initial low pressure "bite" and feel is not the same as the originals - or many other cars to be honest. Although I'm sure these things will last a while as they are big meaty pads too
It isn't a safety issue or problem, it is a get used to the feel thing I've worked out. In any case it could easily be changed with a softer compound brake pad, which is only a choice thing. You could keep the old pads in case you want to change back, but IMO it's not necessary for a safety or performance aspect...just for familiarity with the feel you're used to.

Anyone else with std brakes couldn't go out and stop your car from 60 -80 kph hard on the ABS twice or three times in a 2 minute period and be able to do it another time...without having your brake pedal turn to mush and needing to machine the warped rotors afterwards.

Warning if you try this you will have to replace your brake fluid at the very least....and don't blame me for the horrible shudder you now have when braking down a range...

While I'm not going to give it a go I reckon I could do this 5, 6 or 7 times without boiling the fluid and warping these rotors due to their superior ventilation and heat removal property's.

Not an everyday occurrence sure, but loading and overheating them like that is the closest I can get to trialling them under a similar scenario to heavy towing down a range or something...

[snowman]

I have no problems with my brakes. I run DBA slotted rotors with Bendix pads and whilst the pedal is a little softer than standard (even after fluid flush), they pull up fine and I can activate the ABS quick easily.

Snowy, have you taken it in to get a proper brake analysis? I know that jop had his in for a check up and they found the brakes to be way off balance front to rear and side to side. Maybe you have mud caked in the rears or something.

That's a good idea Joe. http://www.safetstop.com.au/safety_checks.html is the system that Jop had his tested on. The manufacturer is actually right behind our workshop and we know them pretty well. It's a great system and there's a few operators near your area snowie. McGraths is a Mitsubishi dealer but any of the other workshops will do the test for you no problem. It only takes a about 5mins and gives you a complete read out on your vehicle showing brake balance, weight and even alignment to some extent.

McGrath Mitsubishi Liverpool
Terry Shield Toyota in Parramatta
Trivetts BMW in Parramatta.

Sorry i missed that in your first post Joe. So thanks Joe and for the details Brendan. i will get this done as a matter of urgency.

Thanks 'forumates'

[Joe]

No worries snowie. This topic is moving very fast

[Longranger1]

Maybe a check of the vacuum supply to the booster? A low vacuum will make your brakes feel very, very ordinary. It looks like you have done a top upgrade so the brakes should much better than you describe.
Just some thoughts.

[salt36]

I be interested to hear how many owners who get a good 60--80km/h runup on the tar, or dirt for that matter, jump on the anchors (both feet if you want) and get the abs cranking... small little jerky locks...
I have a awful feeling that it is more common than just snowie... I couldnt do it in a MN i drove recent. My brakes are much much better than snowies ML and there is no reason as to why. The fact this particular MN couldnt do it, I initially blamed the 20 inch road wheels having too much grip.... That still could be the case but really brakes should be capable of locking (and having abs relieve them).

Wow, ok.......The only time my abs activates is on mud and i have tested the brakes several times(on bitumen), perhaps I may have a similar problem to Snowy..........as I said above (up there somewhere)my Triton's braking is similar in performance to other vehicles i have owned and thought no more of it.......

Interested to learn what you discover Snowy

Then I can ask Mitsi to look into it

[borngeek]

Very curious on that test.
Good link Brendan nice one! Can you suggest a few round my way and in the interest of information will get mine done and get results to snowie and here of course.

For those experiencing this problem it is very dangerous... There will be that day you need every inch of stopping power and if you cannot lock your fronts on the tar you have a problem IMO and need to sort it. I have never owned a car that did this, I am gobsmacked at your experience salt

Snowie is spending the cash and time as he takes his families safety seriously.(especially with him at the wheel ) But seriously if we both run the test on our vehicles we will have data to process with MMAL.. May as well continue getting them riled up a bit further (hello kids )

//good to read the generous feedback, this site rox!!

[salt36]

^^^ This site does rock BG

Yep mate my 1993 Toyota Landcruiser Disc front and drum rear.....same, poor braking ability

2000 Ford AU fairmont ghia V8 4wheel disc.......Awesome stopping power

2001 Ford Courier twin cab disc front drum rear........same, poor braking

2007 Ford BF11 one tonner 4 wheel disc........Very good stopping

My comparasins have been from 2wd to 4wd and so I have assumed the extra weight and the rear drums has been the factor for poor braking and just got used to it, mind you I do drive the 4X4's a lot slower in town, around schools, shopping centres etc and have done since I first drove the cruiser...............

EDIT - The important stuff, yes family needs to be safe and so does the pedestrian and the drunk who staggers in front of you and the kids who run out of the driveway chasing the ball and the teens riding the pushie with the earphones in and the old lady down the road's dog and the 2 tonne bull that escapes from the paddock ( that is one I definately want to stop for ).............. You know what I mean

[chaser]

Can you get some pics of your front brakes with the wheels off???

As for the 2 disc 2 drum set up, I think that its a great system for heavy payloads etc etc but this system works best with a ton in the back if you catch my drift...

Also have you got bigger tyres than stock??? maybe try borrowing a set of stock wheels and see if they perfom a lot better. If the improvement is only small its something else...

You can upgrade your brakes to the ns paj 4 pistons, but im unsure if they are direct bolt up or not (havent seen one for a while). But u will prob need new rims with a better offset to clear the bigger calipers...

Or buy brembos

[SEJ GLX-R]

I just tried mine, MN big bum auto, standard tyres, no load, at 60km/h and it got the ABS chirping no problem at all.

The Issue sound to me like the master cylinder is leaking fluid back past the piston as others have said,
since yours isn't the only one Snowman, maybe the piston or master cylinder bore were machined wrong in a few

Good luck mate, I look forward to seeing what the test results are.

[Homer]

I'll be doing the brake test thing next week too snowy so will give you results for your comparison/proof.

It's definitely nothing to do with the tyre size as mine and a number of guys on here's are bigger too.

The Paj dual piston upgrade is something I've fantasized about as I've been told they should bolt straight up...bolt centre wise at least.

[snowman]

The paj's run 17's?

[chaser]

yeh i the paj's run 17's i think if i see one next week ill take some pics and put them up. Ill try and compare the 2 and see what i can come up with, but its only ns i think that has 4 pot, as the nt has 2 pot i think... Not too sure but ill do some more research on during the weeks comeing...

[snowman]

thanks mate. i've got 17's so it may be an option but i will see how it goes with the front braids. to be honest with the disc upgrade and everything else working (as most peoples do) i would be happy enough.

looks like the master cylinder might be worth a look after the front brake lines.

yeah the dirt road test was on the muddies but i have standard wheels/tyres now and it still has the same issue under hard braking on good even dry asphalt.

[sam]

Tested ours today on hotmix from approx 90 kmh and it stopped very well and the abs started to kick in but
admittedly with a fair bit of pedal pressure .

[scubapro]

Snowman where did you get your braid lines & how much were they please?