Hi all, I bled the brakes on my KJ as the pedal was dropping too far before anything happens, bleeding has helped but the pedal still drops too far before the brakes work, could this mean the master cylinder needs an overhaul? the pads all have plenty of meat still on them. Cheers

What is the pedal resistance / pedal travel like without power boost?
Does the pedal creep down if you keep it under constant foot pressure?


If bleeding has helped a bit then maybe you still have air in the system.
I usually pump the brakes hard to create micro bubbles and bleed some more (if the pedal feel is still spongy with no vacuum assist).


With all my mitsu cars, the pedal will drop a fair bit with power boost working (ie engine running) and with just moderate foot pressure.
But without power boost (engine not running and vacuum chamber exhausted) the pedal feel is hard and "high".

If there are no obvious leaks in the system and the reservoir level is being maintained, it could be your master cylinder. The seal cups may have deteriorated, hence no leaks out of the system. This happened to my brothers Corolla. Just installed a new Master cylinder kit. It had the symptoms mentioned by aquar. The pedal would eventually make its way all the way to the floor with constant pressure against it.

It is fairly easy to get air into the system when doing a bleed, even if you feel you did it really well.
If you don't have the above mentioned symptoms then I would suggest doing a bleed all over again

It is fairly easy to get air into the system when doing a bleed, even if you feel you did it really well.
If you don't have the above mentioned symptoms then I would suggest doing a bleed all over again

I use a clear plastic hose fitted to the bleed nipple. This allows you to see the air and bubbles leaving the system. Place the other end in a jar and keep on bleeding till no air is visible within the fluid. This method ensures little chance of air entering the system. Air will only enter if you let the reservoir run low while carrying out the bleed or the pedal is allowed to return to the top of its travel while the bleed nipple is open.

When I started to bleed the brakes I was using the hose kit that you use to the bleed the brakes by yourself, but I noticed brake fluid was coming out around the thread of the bleeder valve and I thought well if fluid is coming out air must be going in around the thread so I got my brother to push on the pedal while I operated the bleeder valve, this was two weeks ago, I will check the brakes today going by what the above posts said, well get back and let you guys know how it went, thanks for the replies much appreciated, cheers

Yes that's the problem I think, that air can enter the system not just from the actual nipple opening but rather around the threads etc.

So taking Nigel's directions as an example, air may not come from the tube itself as it is submerged into brake fluid, but from the threads.

ok just checked the brake pedal travel, with the motor off and pumped the brake pedal a few times it felt hard and only dropped about 3 centimetres, with the motor running and pumping the pedal and pushing down hard the pedal would constantly drop about 10 centimetres

Aquar asked, What is the pedal resistance / pedal travel like without power boost?
Does the pedal creep down if you keep it under constant foot pressure? answer the pedal didn't creep down it fell about 3-4 centimetres and stayed there with constant pressure.

Just wondering is better to have the engine running to supply vacuum when bleeding the system or better to have the engine off? I have never had the engine running when bleeding the brakes but just thought I would ask you guys what you thought.

Aquar also asked, If bleeding has helped a bit then maybe you still have air in the system.
I usually pump the brakes hard to create micro bubbles and bleed some more (if the pedal feel is still spongy with no vacuum assist).
Answer, the pedal is not spongy with the motor off but it sure is with the motor on supplying vacuum

With my foot hard on the brake pedal and then start the car the pedal falls away quiet a bit, I would say around 6 to 7 centimetres

No need at all to have the engine runnig. This only provides boost during brake applictions so the pads bite the rotors with less force needed from you're right foot. During bleeding the circuit affected wont be moving the pads as the system is open to atmosphere. Your predicament is why I avoid those kits. As you mentioned air is entering the system as fluid is making its way past the nipple thread. I think you have undone the nipple too far, 1/4 to 1/2 turn should suffice. Even if fluid is leaking past the threads of the nipple, air should not enter the system as long as the nipple is closed before the pedal is allowed to return to the top of its travel. Ensure the nipple is only open when pressure is on the pedal and as it makes its way to the floor as it forces out fluid and any trapped air. As soon as you see fluid stop flowing in the tube immediately close the nipple and repeat the procedure till no air or bubbles are visible.

As mentioned before, dont get carried away and forget to keep the reservoir topped up. Good luck.

No need at all to have the engine runnig. This only provides boost during brake applictions so the pads bite the rotors with less force needed from you're right foot. During bleeding the circuit affected wont be moving the pads as the system is open to atmosphere. Your predicament is why I avoid those kits. As you mentioned air is entering the system as fluid is making its way past the nipple thread. I think you have undone the nipple too far, 1/4 to 1/2 turn should suffice. Even if fluid is leaking past the threads of the nipple, air should not enter the system as long as the nipple is closed before the pedal is allowed to return to the top of its travel. Ensure the nipple is only open when pressure is on the pedal and as it makes its way to the floor as it forces out fluid and any trapped air. As soon as you see fluid stop flowing in the tube immediately close the nipple and repeat the procedure till no air or bubbles are visible.

As mentioned before, dont get carried away and forget to keep the reservoir topped up. Good luck.

When I tried the kit I only opened the valve slightly, only just enough so fluid would come out when pressing the pedal, but I seen fluid coming out through the thread on the bleeder valve, thats when I tossed the kit in the bin and got my brother to come around and help me, I constantly top up the reservoir when bleeding the brakes never let it get below half way so no air has any chance of getting in the system. Air only had a chance of getting in the system when I was using the kit as you are doing the bleeding by yourself, when my brother was helping me I would make sure the valve was fully closed before I asked him to take pressure off the brake pedal. I might try bleeding the brakes again and see what happens, when I was bleeding the back brakes two weeks ago a dark water like fluid was coming out first, think the brakes had not been bleed in years.

When I tried the kit I only opened the valve slightly, only just enough so fluid would come out when pressing the pedal, but I seen fluid coming out through the thread on the bleeder valve, thats when I tossed the kit in the bin and got my brother to come around and help me, I constantly top up the reservoir when bleeding the brakes never let it get below half way so no air has any chance of getting in the system. Air only had a chance of getting in the system when I was using the kit as you are doing the bleeding by yourself, when my brother was helping me I would make sure the valve was fully closed before I asked him to take pressure off the brake pedal. I might try bleeding the brakes again and see what happens, when I was bleeding the back brakes two weeks ago a dark water like fluid was coming out first, think the brakes had not been bleed in years.

Looks like you are on top of it mate. As it is a diagonally split system do the RHD rear followed by the LHD front first. Then do the LHD rear and finally the RHD front. This ensures you are not bleeding out freshly topped up fluid and it gets done in the minimal time.

Looks like you are on top of it mate. As it is a diagonally split system do the RHD rear followed by the LHD front first. Then do the LHD rear and finally the RHD front. This ensures you are not bleeding out freshly topped up fluid and it gets done in the minimal time.

Thanks for that tip, just another thing, when I brake then take off again say at a round about the brakes tend to squeak and thats after I have taken my foot off the pedal, but stops after a few seconds but does it nearly every time I touch the brakes.

Thanks for that tip, just another thing, when I brake then take off again say at a round about the brakes tend to squeak and thats after I have taken my foot off the pedal, but stops after a few seconds but does it nearly every time I touch the brakes.
Could be one of the calipers not fully releasing or resonating after application. It's hard to really tell from here of course. Ensure that the anti vibration plates on the pads are sound. While you are bleeding the brakes, check each wheel spins freely. Had a sticking caliper on my LHD front that prematurely wore out the rotor. The slider pins were heavily corroded. Excessive brake dust on that wheel was also a symptom.

Could be one of the calipers not fully releasing or resonating after application. It's hard to really tell from here of course. Ensure that the anti vibration plates on the pads are sound. While you are bleeding the brakes, check each wheel spins freely. Had a sticking caliper on my LHD front that prematurely wore out the rotor. The slider pins were heavily corroded. Excessive brake dust on that wheel was also a symptom.

cool thanks for that will check the slider pins, sounds like its my drivers side front wheel where the squeak is coming, cheers

Nigel, I get harshness from my brakes when applied.
The higher the speed and the higher the brake force, the more harsh. It disappears below 50km/h.
New brake pads, rotors, and llubed pins.
Any idea of what this could be?

What do you mean exactly by "harsness"? Do the brakes squeal? Do the pads vibrate when applied? Sorry for the delay getting back to you. Busy with family over Long WE.

No squeal, but yes it seems like the pads vibrate or something. Feels like they grind almost but they don't actually grind on anything.

No squeal, but yes it seems like the pads vibrate or something. Feels like they grind almost but they don't actually grind on anything.

There is a spring plate located inside the caliper that goes against the outside edge of the pads to ensue they are held in place and dont move around excessively. Check to see its in place and has suffecient tension against the pads. Also check that the shims are located correctly and arent free to move.

There is a spring plate located inside the caliper that goes against the outside edge of the pads to ensue they are held in place and dont move around excessively. Check to see its in place and has suffecient tension against the pads. Also check that the shims are located correctly and arent free to move.

I can vouch for the fact that without the shims in place, the brakes feel bad.

Could be one of the calipers not fully releasing or resonating after application. It's hard to really tell from here of course. Ensure that the anti vibration plates on the pads are sound. While you are bleeding the brakes, check each wheel spins freely. Had a sticking caliper on my LHD front that prematurely wore out the rotor. The slider pins were heavily corroded. Excessive brake dust on that wheel was also a symptom.

Just checked my front drivers side brake caliper, the top slider pin is fine but the bottom one is stuck in hard wont move, I'm worried I will snap it off trying to get it to move

Just checked my front drivers side brake caliper, the top slider pin is fine but the bottom one is stuck in hard wont move, I'm worried I will snap it off trying to get it to move

Update, got the pin out it was stuck in there pretty hard

There is a spring plate located inside the caliper that goes against the outside edge of the pads to ensue they are held in place and dont move around excessively. Check to see its in place and has suffecient tension against the pads. Also check that the shims are located correctly and arent free to move.

I don't have shims on my brake pads. Where do I buy them from?

Edit:
As for those springs, yes they are installed correctly.