help needed on brake!

[sledgehammer]

sifu all,
i need some help here to determine what is the problem with my waja 1.6

my brake pedal is spongy intermittently.... yes, intermittently....
sometimes when i brake, the pedal distance is very far, somehow i need to floor it and yet the pressure applied is little.....
but sometimes it is just fine, when i just step on the pedal a little, the car would come to a halt...

recent discoveries was the brake pedal travel distance is more consistent if the aircond is off throughout the driving...... but i cant really off the aircond everytime... our weather is just... HOT....

previously i tot it is bubbles inside brake hose and had my brake fluid flushed and topup with dot4..... but the problem reoccur after the next day....
a mech managed to change the brake valve connecting to master cylinder but the problem wasnt completely resolved ... just the brake not that bad compared to previous times.... :confused_smile:

any sifu can advice???

 

[TitanRev]

Bro, is your Waja a new car ? How old is your car already ?

Try checking your brake hose to see is there any aging sign or crack.
and also check your caliper pot oil seal to see any leaking.

I'm not sure about your problem but trying to help you out here.
is your brake fliud level over the Max line or just at the Max line ?

 

[sledgehammer]

i got mine 2nd hand.... yr 02
that time dunno anything about car, so bought the car without having expert with me...

i got 3 different mech inspected b4.... the first mech had checked and replace the brake valve... which managed to solve the prob little bit...
the next mech advised to change brake pad, coz he said it might due to brake pad...after inspecting the current pad (which has worn out quite badly), i changed all 4 pads.... the pads has run in now but problem still there... during changing pad, the brake hose was inspected as well but no sign on leakage. but for caliper pot oil seal, not really inspected.... but leakage shd be seen during changing pad rite?
the 3rd mech was 3 hour ago... he can't find any leakage at master pump n servo as well... so he is not sure what is the prob... :(

the brake fluid level was roughly 1mm lower than max line....
since the last bleeding, the brake fluid is at the similar level .....

i'm pretty confused now....

 

[sledgehammer]

forgot to add....

the brake pedal distance will get worse in the jam....

if my car is constantly miving, the pedal distance is not that bad....
if i drive the car aggresively (e.g. rev to 3.5k then change gear), the brake will become very 'normal', which the car can come to a stop even if i step on the brake lightly....

 

[ken12292703]

how about the vaccum hoses?
any lost of fluid? if there's lost of fluid means leaking externally
if no lost of fluid, master pump kit have to be changed

from past experince, master pump and caliper piston seals give troubles. check it before it's too late. Mine having problems too.

 

[sledgehammer]

vacuum hose is the short hose connecting fr throttle body to engine rite?

that one inspected as well, no leakage....

this morning driving to kl, which jam all the way, i experience no braking problem with aircond off.......
seemed that turning on the aircond causing vacuum leak.... possible ar?
may i know where is the caliper piston seal located? at the brake caliper?

many thanks!

 

[ken12292703]

Yup, the seals are inside the calipers. Get them changed so that you won't get worried next time. It's for your own safety as well. Servicing brake system for me is no regret matter even it's not 90% wear off or not spoiled yet. So that you can brake with confidence.

 

[sledgehammer]

so ken, shd i worry about leaking vacuum??

 

[drebar]

sledge, r u in penang?

 

[vladimir]

sometimes ur technician tweak ur brake so u wont get the fast brake.

u need to floor it to brake it. so far i heard that it will reduce bearing rosak mah~

u better check with your technician lo if u wan fast brake...

 

[sledgehammer]

drebar: nope... i am in KL. :)

vladimir: hehe, i think not for my case ler, coz the pedal distance varies fr time to time.....coz i may need to floor my brake for this minute, but for the next 10 minute the pedal can be responsive back.....

 

[ken12292703]

Hie bro, Gong Hei Fatt Choy! I changed my caliper seals and rings before. The results are great as they take out and you have a look for yourself. If the previous owner didn't change the brake fluid every year, then it'll be very very dirty and the fluid almost dark in colour. Vaccum hoses also very important. Check everything before it fails.

If there's fluid lost, their is external leaking. Check everywhere the fluid flows.

If there's no fluid lost and the brake pedal to the metal, then the master servo have to be checked again. If you have changed the kit only, then it might be the kits problem because the kit might not work 100% as i experienced before, after repairing, half way home, no brake! WTF! Have to use hand brake and 1st gear to go back to the mechanic. Maybe you can go for a bleeding process again for all.

Have a safe journey everywhere!

 

[ken12292703]

Mine is different, mine for the first 15 minutes, the pedal is damn responsive. After 15 minutes, everything heats up and it goes down. Have the whole master pump changed and problem solved. Kits are cheap but not really reliable as the pump cylinder may wear and causes leakage even after the new kit is in.

 

[drebar]

oh..nvmnd...if in penang, there is a shop called AMW...

 

[TitanRev]

Bro sledge, check out the latest issue of Hypertune. They got a write up about brake system.
Hope it can help you out a bit.

 

[SkYwAlKeR]

get urself steel braided brake hose if problem still persist after solving all the above... old rubber brake hose will expand when more pressure is applied...

 

[sledgehammer]

thanks guys for all the info

will bring my car for checking after this CNY.... especially the master brake pump

Happy New Year everyone and most important of all, drive carefully with ur 4wheels monster! safety first!
:)

 

[ken12292703]

Hello bro, please tell us the problem if it is solved. Thank you very much.