gq brakes

[69darocket]

hi all. i am having major dramas leeding the brakes on my gq. read heaps of posts on forums and come to th conclusion that i need to da a vacuum bleed on the ol' girl. just wondering if anyone can tell me how to do this please and the procedure please. having never done this before. thanks heaps on advance.

rod

[ycantigothere]

hey mate ,im no mechanic but i just followed directions from the gregorys manual and had the missus pumpin the brake pedal and all worked out ok ,cheers ben

[Finly Owner]

Ok I'm presuming GQ is same as MQ. As I was thinking of my clutch bleed I did, I can't remember to fluid circiut for brakes, without checking. But, Bleed master cylinder first,then proceed through any in line nipples, before proceeding to each wheel individually. Have a look in this thread http://www.nissanpatrol.com.au/forums/showthread.php?771-gq-3l-having-trouble-bleeding-clutch.&highlight=brake+bleed some of that stuff is same as brakes.

Tim

[patch697]

Have you pulled out each bleeder & checked them for blockages? If not do so as this will stop any attempted brake bleeding dead in its tracks.

When bleeding brakes start at the rear left wheel moving on to the rear right moving on to the front left & finishing at the front right.

If you have already done all of the above mentioned with no luck I suspect you have a either a failing master cylinder or a breach in the system somewhere as I have bled many GQ's both rear drum & rear disk & have never had to use a power bleeder (vacuum bleeder) on a healthy braking system.

To answer your original question a power bleeder (vacuum bleeder) is a small simple device that runs of an air compressor. you put the tube (its normally clear) on the power bleeder over the bleeder nipple, crack it open as you would when bleeding brakes manually & push the button on the power bleeder & it sucks the fluid though. When you can no longer see air bubbles in the tube lock the bleeder off then take your finger off the button, check the fluid level in the master cylinder & move on to the next wheel. Start at the left hand rear wheel & continue using the sequence mentioned above finishing at the front right.

I can not state strongly enough that I would only recommend using a power bleeder on a healthy braking system as this could hide, mask, preexisting problems in your braking system that will lead to brake failure in the future.

I hope this helps & don't hesitate to ask more questions if you need to.


Best of luck.

[69darocket]

ok, just an update.

finally been able to bleed the brakes. it seems that the new pads (bendix) had pretty much cooked themselves (hence the sloppy/spongy pedal feel). i find this very strange for a top notch pad, yes they are getting changed free of charge. pedal is solid now just seems like a lot of travel. could this mean failing rotors ? not sure how old they are but for the life of me i can't get the fronts to lock up, no matter how hard i try. thanks to all replies, both past and future ones.

[growler2058]

ok, just an update.

finally been able to bleed the brakes. it seems that the new pads (bendix) had pretty much cooked themselves (hence the sloppy/spongy pedal feel). i find this very strange for a top notch pad, yes they are getting changed free of charge. pedal is solid now just seems like a lot of travel. could this mean failing rotors ? not sure how old they are but for the life of me i can't get the fronts to lock up, no matter how hard i try. thanks to all replies, both past and future ones.

Im no expert but iwould not think the rotors would be a the cause unless they are extremely glazed up, or have been over machined which would be very irresponsible of someone to do even then i would av thought they would still lock up, i would be more inclined to think the caliper is U/S

[patch697]

ok, just an update.

finally been able to bleed the brakes. it seems that the new pads (bendix) had pretty much cooked themselves (hence the sloppy/spongy pedal feel). i find this very strange for a top notch pad, yes they are getting changed free of charge. pedal is solid now just seems like a lot of travel. could this mean failing rotors ? not sure how old they are but for the life of me i can't get the fronts to lock up, no matter how hard i try. thanks to all replies, both past and future ones.

If you are telling us you have just replaced the pads today then I would expect thay are not getting fall contact with the disc at this stage as thay have not had a chance to fully bed in (this takes at least 200+ kms). this can give the brake peddle a spongy feel & have your brakes feeling a little off.

If you read the instructions thay will explain how to bed them in properly so you don't glaze the pads which is more likely to occur on brand new pads as a result of over heating the new pads before thay have bed in properly.

Part of this will read: "Try not to over heat your new pads by means of hard or excessive braking in the first 200 kms" So no more trying to get the brakes to lock up cos you might end up damaging your new pads & this will prevent them from bedding in properly & you will end up with pore feeling bakes for the life of the pads.

As I said just have a read of the instructions, thay lay it all out for you in them.

Good luck & lets hope your all sorted & everythings feeling good after your brakes are bed in.

[YNOT]

It would be a good idea to get your rotors inspected and measured, then again I recently picked up a pair of brand new GQ front rotors for about $100 - hardly worth getting them measured up at that price.

Your lock up issue could be your brake load sensing bias valve in need of adjustment.

Tony

[69darocket]

cool. thanks guys for the advice. i tried to lock up the front with the old pads but only got a "hard braking" motion. and installed the new pads. i'll be chasing up some new rotors, found some rotors brand new for a bargain, gotta love defence discount, and the load sensing bias valve tonight to see how it works and start tweaking away. lol. gotta love troubleshooting systems, always start from the start. thanks heaps for all the input guys. heaps appreciated.

[Silver]

Excessive pedal travel could indicate too much movement in the front wheel bearings.

If you are going to replace front rotors you may want to pick up wheel bearing kits anyway...... and then you are only a few more bolts away from replacing the swivel hub bearings and seals, and a peek at the CVs.

Where does it all end :-)

[timbar]

could also be calipers my just need an overhaul they could be a bit sticky my brakes were up the sh!t and i overhaled the calipers bleed the system and bingo they were 100 % better than they were and also the brake load sensing valve make sure its not leaking mine was and even the brakes mechanics didnt pick it up on it

[Finly Owner]

Did your pistons move freely back when placing in new pads in calipers?

Tim

[timbar]

mine ???? mine were hard as took a lot of effort to get them all the way back

[patch697]

mine ???? mine were hard as took a lot of effort to get them all the way back

Next time if thay are hard going back try cracking the bleeder... it can help

[timbar]

the pistons were seized thats why i had to overhaul them

[blake_gq4.2]

just a quick question, does it have drums on the rear? if it does if the rear brakes r out of adjustment it will give a shithouse pedal, and also if the wheelcylinders are leaking, cheers blake

[Finly Owner]

mine ???? mine were hard as took a lot of effort to get them all the way back
No Rockets ones......we are trying to help him I think, oh sh1te, I've lost rack.LOL