Soft brakes

[CarlJT]

After changing pistons on front brakes and bleeding. Certainly not seeing Any air coming through lines, soft spongy brakes, pressure builds up at stand still drops when move. Handbrake only kicking in when fully up. Is this air? I've spent a while bleeding each line and am not seeing any air bubbles. Using 2 person method. Is there any way to get stubborn air out, if that is the issue. Or any other possibilities. Not seeing any leaks throughout lines/ at new pistons

 

[Old.Tony]

On my car (2009 D40) the handbrake is on a cable and is entirely not attached to the hydraulic system. I'd suspect your car would be no different.

Spongy brakes can be caused by several things:

* Air in the hydraulic lines
* Damaged/degraded brake hoses expanding under pressure
* Sticking pistons in calipers/drums
* Vacuum leak in the booster
* Damaged booster
* Leak in/damaged ABS unit

Some of those are fairly easy to find (observation while brakes being depressed, and no I don't mean sad). A vacuum leak will often correlate with poor turbo performance since those systems are connected to each other. Look around and under the ABS unit for leaks, not sure where it sits in the D22 engine bay but it will have five thin metal tubes coming out of it.

Is it consuming any brake fluid at all? That will spell "leak" somewhere.

 

[CarlJT]

On my car (2009 D40) the handbrake is on a cable and is entirely not attached to the hydraulic system. I'd suspect your car would be no different.

Spongy brakes can be caused by several things:

* Air in the hydraulic lines
* Damaged/degraded brake hoses expanding under pressure
* Sticking pistons in calipers/drums
* Vacuum leak in the booster
* Damaged booster
* Leak in/damaged ABS unit

Some of those are fairly easy to find (observation while brakes being depressed, and no I don't mean sad). A vacuum leak will often correlate with poor turbo performance since those systems are connected to each other. Look around and under the ABS unit for leaks, not sure where it sits in the D22 engine bay but it will have five thin metal tubes coming out of it.

Is it consuming any brake fluid at all? That will spell "leak" somewhere.

No leaks, not consuming.
These models don't have abs. Wondering if it's lack of pressure and master cylinder need replacing

 

[Old.Tony]

No leaks, not consuming.
These models don't have abs. Wondering if it's lack of pressure and master cylinder need replacing

That's about the point where I'd hand my car to a mechanic/brake specialist and tell them what I've done, what I've noticed and get them to finish it. Thankfully, in the small rural town where I live, I can talk to the guy at the counter, and he'll send out the actual guy who'll work on my car to have a look over it with me, so there's no chance of the message changing as it is told to others. I have no means to test those things, I could do the observations (like expanding brake lines) but not a master cylinder test.

 

[[email protected]]

a little or maybe most of the spongy feel is rear adjustement to hand brake. its adjustable through the slots where the diff meets the brake dust cover. sometimes you have to remove wheel and drum to free the adjuster ,i think you will find it may have the auto adjuster there check it engages the slotted nut firmly . when adjusting you lock the wheel then back adjuster off nut you will hear minuete conact when you turn the wheel it must spin freely, hitting brake pedal at this stage to make sure pads are centered.. by adjusting the rear shoes the rear pistons have less travel.The hand brake should locks rear wheels about 3-4 clicks off disengaged position, count clicks as you pull lever, I have had the drums wear exessively and the cam flipped over with the shoes making little contact,(this was the cause of spongy brakes on may car) when you replace shoes sit new ones into used drum the new shoes wont make full contact on even slightly worn drum..Occasionally the adjuster where cable forks needs slackening off , and also you may have adjuster under your console handbrake boot... If i remember correctly these 2 adjustesr is only used for adjustement if the cable stretches, eg the rear shoes are adjusted properly but your hand brake lever still pulls out fully or more than 3-4 clicks
I always take drums to brake and clutch , they measure the inside diameter of the worn drum then they have a machine that trims the new shoes so that the full surface makes contact with the drum. if they are exessively worn they will recommend new drums . they trim shoes to fit each individual job.. Test the vacuum no motor running engage brakes .then start the car pedal should drop some, not down to floor If you buy new parts drum and shoes you still have to sit them in and do a visual shoes may still need trimming.. remember with brakes and tale sharfts you are playing russian roulette , you make one mistake and it may cost a life

 

[tweak'e]

Handbrake only kicking in when fully up

rear brakes need adjusting.

 

[CarlJT]

Have tightened rear drums. Big improvement but still feels slightly soft on pedal. Doing brake test on gravel rear locking up first and even. Not noticing a huge amount of braking force in front.

 

[Old.Tony]

What condition are the front pads in, and are they sintered or organic?

I put an organic pad on my motorbike, the braking performance is remarkably different to sintered. Organics were supposed to be similar in performance, but I notice that I only get one good handful of brake and then it's like they've faded, and I have to wait for a minute or so for the disc/pads to cool. If I have to brake hard in between, it basically ignores me. Dot 4 fluids, hoses all good, cylinder all good, put in sintered pads and everything works fine. Except the disc wears faster. There's no noticeable wear with organics.

 

[Horatius]

After changing pistons on front brakes and bleeding. Certainly not seeing Any air coming through lines, soft spongy brakes, pressure builds up at stand still drops when move. Handbrake only kicking in when fully up. Is this air? I've spent a while bleeding each line and am not seeing any air bubbles. Using 2 person method. Is there any way to get stubborn air out, if that is the issue. Or any other possibilities. Not seeing any leaks throughout lines/ at new pistons

Sounds like air in the lines.

I replace my brake fluid every second big service. Use one of these which works a treat.

 

[Erick]

How spongy? When new pistons and seals installed, the piston will retract a little bit further than when old. This is enough to make the pedal feel a little more travel and feel spongy. But only a little bit- maybe an extra 10-20 mm travel. Rear wheels locking up first on gravel is not unusual, especially if it’s a Ute. Did u replace pads as well? If not did they go in exactly as they came out? It don’t take much to upset brakes.

 

[CarlJT]

What condition are the front pads in, and are they sintered or organic?

I put an organic pad on my motorbike, the braking performance is remarkably different to sintered. Organics were supposed to be similar in performance, but I notice that I only get one good handful of brake and then it's like they've faded, and I have to wait for a minute or so for the disc/pads to cool. If I have to brake hard in between, it basically ignores me. Dot 4 fluids, hoses all good, cylinder all good, put in sintered pads and everything works fine. Except the disc wears faster. There's no noticeable wear with organics.

Brand new ceramic

 

[CarlJT]

How spongy? When new pistons and seals installed, the piston will retract a little bit further than when old. This is enough to make the pedal feel a little more travel and feel spongy. But only a little bit- maybe an extra 10-20 mm travel. Rear wheels locking up first on gravel is not unusual, especially if it’s a Ute. Did u replace pads as well? If not did they go in exactly as they came out? It don’t take much to upset brakes.

Brand New exsaxtly same. Brakes before were seized replaced almost everything, may just feel softer due to everything being new? Went in same way. They feel soft. Very little braking power with foot down. When 3/4 down starts to bite firmer but feel like it should have a stronger bite from half way down...

 

[Old.Tony]

I've never driven with ceramic pads before, so my experience ends here.

 

[[email protected]]

when stopped ,if you pump the brakes and pedal becomes firmer then its air ,,,,brake load sensing valve ??? Since the proportioning valve decreases the pressure sent to the rear brakes, the main symptom the valve is going bad is the rear wheels locking up when the brakes are applied. Furthermore, the wheels will lock up more easily on wet surfaces. The rear brakes may feel touchy when applied even gently. Increased Braking Distance. other causes abs no redirecting properly
some interesting info i wasnt aware of adjusting load sencing proportioning valve on mitsubishi some info should be on net for Navara

 

[[email protected]]

load sensing valve has a bleader on it

 

[CarlJT]

Do front or rear need to lock up first?

 

[pol327]

A few things here.
It is best to try your brake application tests on bitumen if possible. Lock up under heavy application and if this does happen, should be on all four wheels, that is if the brakes are functioning correctly and set up correctly. Not one before the other.
Is the load sensing valve working properly and allowing pressure reduction to the rear when unloaded ? I have seen a few of these fail.

Rear brake adjustment for drum brakes. Some people use the park brake cable to 'adjust the rear brakes'. The first thing to do before attempting to adjust the rear shoes is :
1. An inspection to make sure they are in good order and de-dust them.
2. Back the park brake cable adjustment off.
3. Adjust the rear shoes as previously described. Lock the brakes up using the adjusters, then release the adjuster so the wheel spins freely with light scraping but not dragging.
4. Then adjust the park brake cable.

If your pedal is spongy and this is 'a non abs vehicle' then inspection of all flexible lines is required. Not only for expansion which as said will give a spongy feel but also for blockages that will affect applied pressure. Check all your steel lines for damage as well.

If you pump the brakes and the pedal becomes firmer then this is NOT air in the hydraulic circuit, it is an adjustment issue. Air will not compress in the lines to give a better pedal, that is a hydraulic fact. My experience with ceramic brake pads is that they require more applied pressure compared to metal or organic pads.

At the end of the day and as already suggested if you still have an issue then take the vehicle to a brake specialist, explain what you have done and get the issue resolved.

 

[tweak'e]

load sensing valve has a bleader on it

yes, keep in mind there is a certain order to bleed the brakes in.

 

[CarlJT]

Have done all suggested. Took on road and had no issues. Testing from 50k hard and 80ks medium strength. No issues however still feel slightly soft so will get checked asap to be certain. Atleast their 10x better than before. Thanks for help

 

[[email protected]]

as a point of interest abot 20 yrs ago i had a friend turn up in an old toyota truck, when he put on his brakes i noticed he was pushing with all his strength and truck slowly came to a stop, i asked him if he was having trouble stopping and he said yes, just spent $800.00 dollars at clutch & brake workshop on new front and rear brakes but truck still wont brake properly. I lifted up the bonnet ,showed him the vaccuum pump conected to alternator , disconnected the vacuum hose got him to feel there was no vacuum and told him to go back to workshop and show them.. occasionally even the experts can miss diagnose, still its better them than us with limited experience.