Brake system help for MOT

[sleepy]

Hi

I have been searching through the brake threads to try and find an answer to my questions but need to check a coup!e of things.

I have a 3.0 TD 4runner and had replaced the front pads discs and calipers with new items bled the system as normal and no issues. The only thing it failed the mot on was hand brake efficiency and one of the pipes at the rear at lsv corroded. I found after taking drums off that the shoes needed replaced so I did that and cleaned the inside. I replaced both pipes on the rear axle and the one that goes from lsv to rear flexi.

Questions are how effective should the handbrake be, is it supposed to stop the vehicle if its in gear and you let it out on clutch pressure? It seems to be tight after adjustment but still moves when clutch is out only just though, there is resistance.

The other thing that is now happening is the brake pedal sinks towards the floor when you hold it with hard push when engine is running, I can't remember it doing that before...with engine off the pedal stays firm. I have bled the rear brake a few times now with no air coming out and it still seems the same. If I pump the pedal with the engine running the brake warning light flashes on. Reading posts this could be vacuum issue or master cylinder or is it something else that could be happening as this was fine after I replaced the front brake system and has only started since I did the rear, could it still be air?

[sleepy]

Any help appreciated as I have retest for mot tomorrow. Just going to have a look at everything again just now
Should also mention, no leaks visabke anywhere and fluid level stays the same

[sleepy]

OK so after reading about vacuum possibilities I just tested again. The pedal only goes towards the floor with engine running while vehicle is sitting still and when firm constant pressure is placed on the pedal, if I pump the pedal enough the brake warning light will flash on. If I rev the engine while pumping the pedal the warning light doesn't flash on. The problem has only appeared since I replaced the rear break pipes and shoes.

Is this definetley a vacuum issue or could it still be air somewhere in the system. If it is vacuum where could it be, I have checked vacuum pipes and they seem to be OK.

Also the handbrake is tight and firm but still only just moves vehicle when clutch is let out when in gear, what could be the issue with this or is this within normal tolerance, the shoes are new so have not been bed in properly either.

[tintin]

i had all the same issues with mine a long while ago!
No - one ever told me an answer to why the pedal slowly goes to the floor!!!!
i did however get the brake system "pressure bled" by a local 4x4 garage.. It really did help to get rid of the air from the system, and almost eliminated the drop to the floor ( but not quite)

Alan

[tweak'e]

a lot of the vehicles with LSV need to be bleed at the LSV or the brakes in a certain order. can't remember what it is for surfs.

many years ago i had a car that kept sinking the pedal to the floor. replaced everything. talked to old mech and he said to change the drums. sure enough change the drums and it was fine. i suspect the drums where to worn and allowing to much rear brake travel which requires a long pedal travel to supply all the fluid to them.

[RebelV8]

I bled mine last year, you need to start with the wheel furthest away from the master cylinder, then the next furthest etc etc

[tintin]

AND don't forget to bleed the LSV

[sleepy]

Hi all,

Thanks for the responses.

Bled the system over 5 times going from nsr to osr to lsv to NSF to OSF each time, I even back bled and just let lots of fluid run through each bleed valve on the last one...no air was present on any of the bleeding attempts except the very first time. The only thing I noticed was that the osr hand brake was adjust too ight as it wheel was not moving even with hand brake off when it was on axle stands. I took the the drum off again and readjusted it again leaving g the bleed valve open while I pushed the piston pins back in...must have been air stuck in there or the pistons In rear drums where stuck out or something as when I put it together again it is OK now and has passed mot.

Bit confused still as to what the issue was and I will be keeping an eye on it to ensure there is no air stuck In it still!

If any further developments I will update the thread but all good now :-)

Thanks for the help

[Diezel Weazel]

Glad ya got it sorted !!
FYI .... Generally when pumping the pedal when stationary n the pedal rises higher = means the brakes need adjusting n centralizing ....

15+ Years of Surfs .... n Faultless to a "T" is my Yota !! So I got another ....

[sleepy]

Thanks diesel weasel, think it may have been something to do with that as after I readjusted the osr drum again the problem seems to have gone...I scanned all the threads and never saw that mentioned that's why I was thinking it may have been something else...ah well i'm learning more and more about this jeep all the time ;-)