auszookers.com
https://auszookers.com/forum/

no brake pedal pressure
https://auszookers.com/forum/viewtopic.php?f=5&t=41808		 Page 1 of 1
Author:  whincup [ Mon Jul 08, 2013 4:10 pm ]
Post subject:  no brake pedal pressure
I have a suzuki maruti, and I've just replaced my master cylinder, rebuilt LWB vit calipers with new rotors and pads to suit, and brand new extended flexible lines . For some reason they will not fully bleed properly. I bench bled the MC, I used a clear hose as a one man bleeder for the calipers. so with that over the bleed nipple, i pump away at the brake pedal, and while doing this the fluid is coming out air free, but once i stop, within a matter of seconds air bubbles start coming out of the bleed nipple. i've gone through about a litre of brake fluid and it isnt getting any better.

originally i rebuilt the caliper myself, but had it redone by the local brake experts thinking i'd fucked something up but no difference. im also aware the caliper has to be twisted to make the bleed nipple the highest point and have been doing so... what the hell am i missing?? no fluid is leaking anywhere and the time from when i stop pumping to when the bubbles start coming out suggests the leak is in or near the caliper somewhere... but both sides are doing exactly the same thing!

It's booked in for the end of the week, but anyone have any ideas??



--new issue posted below
Author:  atari4x4 [ Mon Jul 08, 2013 10:38 pm ]
Post subject:  Re: Air in Brakes - leaky seal??
It's not leaking air via the threads on the bleed nipples?
Author:  fordem [ Tue Jul 09, 2013 2:52 am ]
Post subject:  Re: Air in Brakes - leaky seal??
^^ I've see that happen - the fluid in the bleed tube flows under it's own weight creating a vacuum that draws fluid through the system and can also pull air in around the bleed nipple threads.
Author:  whincup [ Wed Jul 10, 2013 5:05 pm ]
Post subject:  Re: Air in Brakes - leaky seal??
That actually ended up being it, wish i'd thought of it earlier... fix was to bleed it the old fashion way haha, cheers. wish i'd been smart enough to check it earlier... but i still cant get rid of the spongy pedal. i can pump it a few times and it hardens up, but once its untouched for more than a few seconds it just goes 3/4 the way to the floor. front wheels lock on grass (havent driven on the road to test tarmac yet) so i know they work fine, but if i clamp the rear brake hose, the pedals nice and firm so its definitely something in the rear. I thought they were self adjusting, but is there something I'm meant to do first??
Author:  atari4x4 [ Wed Jul 10, 2013 5:10 pm ]
Post subject:  Re: Air in Brakes - leaky seal??
yeah it's actually quite common. try jumping on the brakes a few times in reverse (steak_knife trick) and adjusting the rear shoes up & the handbrake as per the FSM.
Author:  whincup [ Wed Jul 10, 2013 5:23 pm ]
Post subject:  Re: Air in Brakes - leaky seal??
yeah did the rear brake adjust, im using an SJ413 manual but im fairly sure its the same as WT maruti, could be wrong? did the forwards & backwards thing, fast as it would go in reverse then forwards in 1st half dozen times... no difference. might have a go at handbrake adjustment, it does get hard as you would expect a handbrake lever to as you pull it up, but it doesnt hold on hills well...
Author:  atari4x4 [ Wed Jul 10, 2013 5:28 pm ]
Post subject:  Re: Air in Brakes - leaky seal??
the rear shoes need to be pretty tight on the drum, some more info in this thread that would be applicable to the sierra: viewtopic.php?f=5&t=41468&hilit=drum+brake
Author:  whincup [ Wed Jul 10, 2013 5:36 pm ]
Post subject:  Re: Air in Brakes - leaky seal??
atari4x4 wrote:
the rear shoes need to be pretty tight on the drum, some more info in this thread that would be applicable to the sierra: viewtopic.php?f=5&t=41468&hilit=drum+brake


Excellent, I'll go give that a go. cheers!
Author:  whincup [ Thu Sep 05, 2013 3:16 pm ]
Post subject:  Re: Air in Brakes - leaky seal??
so i've had a chance to do a bit of forward and back actions up the driveway, around the block (sat in middle of the road forwards and reverse, dunno what the neighbors thought of that!) and its minor improvement... if i dive on the brake, it still bottoms out on the floor, however i can hear the front wheels borderline locking, so brakes do work but i dont like the pedal feeling like that. if i clamp the rear line, the pedals about perfect, brakes take effect almost straight away and is a firm pedal, very similar results if i clamp both front lines, to a lesser extent if i clamp just one or the other front line... it just feels like the master cylinder isnt moving enough fluid at all, but its brand new and specified it was to suit WT maruti. how much difference (if at all) is there between the maruti and SWB sierra's? ignoring the booster, does either move more or less fluid??

it's been spongy ever since i've owned it. EVERYTHING is new, except the drums which were measured to be within spec, metal lines and rear rubber hose which looks and feels fine. has rebuilt LWB vitara calipers as well which i think i mentioned earlier, but it doesnt feel any worse with those over the original calipers...
Author:  Zook_Fan [ Thu Sep 05, 2013 3:26 pm ]
Post subject:  Re: Air in Brakes - leaky seal??
whincup wrote:
EVERYTHING is new, except the drums which were measured to be within spec, metal lines and rear rubber hose which looks and feels fine.


Including the proportional valve?
Author:  whincup [ Thu Sep 05, 2013 4:37 pm ]
Post subject:  Re: Air in Brakes - leaky seal??
Zook_Fan wrote:
whincup wrote:
EVERYTHING is new, except the drums which were measured to be within spec, metal lines and rear rubber hose which looks and feels fine.


Including the proportional valve?


thats the one that sits below the MC, 2 lines in and 3 out? i'd forgotten about that, no... would that cause a brake pedal to feel like a clutch pedal?
Author:  Scrawny [ Thu Sep 05, 2013 5:04 pm ]
Post subject:  Re: no brake pedal pressure
Were the drums machined?
Author:  atari4x4 [ Thu Sep 05, 2013 5:15 pm ]
Post subject:  Re: Air in Brakes - leaky seal??
whincup wrote:
Zook_Fan wrote:
whincup wrote:
EVERYTHING is new, except the drums which were measured to be within spec, metal lines and rear rubber hose which looks and feels fine.


Including the proportional valve?


thats the one that sits below the MC, 2 lines in and 3 out? i'd forgotten about that, no... would that cause a brake pedal to feel like a clutch pedal?


nah, pretty sure that's the distribution block, the LSPV (Load Sensing Proportioning Valve) is up the rear somewhere (it is one a vitara)
Author:  whincup [ Thu Sep 05, 2013 5:23 pm ]
Post subject:  Re: Air in Brakes - leaky seal??
no, local brake shop said they were smooth enough to not need more than a quick wipe of brake cleaner. i took the whole rear drum and axle assembly in to make sure it was assembled correctly and the parts all matched each other (2 different shoe/drum sizes listed, and apparently 3 brake cylinder sizes listed) and they said all was fine... even if they did need machining that would only affect how well the rears work, not the pedal pressure wouldn't it?

I'm ready to burn the bastard... i have receipts for close to a grand spent on new brake components!

atari4x4 wrote:
nah, pretty sure that's the distribution block, the LSPV (Load Sensing Proportioning Valve) is up the rear somewhere (it is one a vitara)


pretty sure maruti's dont have anything like that... if they do, im missing it, and theres no bolt holes in the chassis where its meant to be mounted. my old SWB WT sierra had one...
Author:  Scrawny [ Thu Sep 05, 2013 5:24 pm ]
Post subject:  Re: no brake pedal pressure
I've had issues with spongy brakes due to big lips worn in the drums, the shoes don't contact properly and won't self adjust far enough.

Sounds more like an air-in-the-line issue to me
Author:  Marko_SJ [ Thu Sep 05, 2013 5:28 pm ]
Post subject:  Re: no brake pedal pressure
Scrawn wrote:
I've had issues with spongy brakes due to big lips worn in the drums, the shoes don't contact properly and won't self adjust far enough.

Sounds more like an air-in-the-line issue to me


Sorry to the OP for a quick hijack, but mine are like that on the drum, and I get good pedal feel right at the end of the pedal travel. Brakes work fine though.

For the sake of being retentive, changing the drums out or having machined is a way to fix that?
Author:  whincup [ Thu Sep 05, 2013 5:31 pm ]
Post subject:  Re: no brake pedal pressure
Scrawn wrote:
Sounds more like an air-in-the-line issue to me


yeah a mechanic mate of mine says the same thing, but i've run about 3 bottles of brake fluid through it trying to bleed it, no success...
Author:  Scrawny [ Thu Sep 05, 2013 5:47 pm ]
Post subject:  Re: no brake pedal pressure
whincup wrote:
Scrawn wrote:
Sounds more like an air-in-the-line issue to me


yeah a mechanic mate of mine says the same thing, but i've run about 3 bottles of brake fluid through it trying to bleed it, no success...


How are you bleeding? Manually, vacuum or gravity?


The_Amateur wrote:
Sorry to the OP for a quick hijack, but mine are like that on the drum, and I get good pedal feel right at the end of the pedal travel. Brakes work fine though.

For the sake of being retentive, changing the drums out or having machined is a way to fix that?


I'd be getting them machined for starters and going from there. It may only be half the problem tho. Poorly adjusted front wheel bearings can add to it as well.
Author:  mrw82 [ Thu Sep 05, 2013 5:49 pm ]
Post subject:  Re: no brake pedal pressure
You've got lwb vit calipers on the front don't you? Don't people normally run them on sierras to equalise proportioning when doing rear disks? Given that you still have drum rear your proportioning could be out of whack giving you poor pedal feel.
Author:  Marko_SJ [ Thu Sep 05, 2013 5:59 pm ]
Post subject:  Re: no brake pedal pressure
The_Amateur wrote:
Sorry to the OP for a quick hijack, but mine are like that on the drum, and I get good pedal feel right at the end of the pedal travel. Brakes work fine though.

For the sake of being retentive, changing the drums out or having machined is a way to fix that?


Scrawn wrote:
I'd be getting them machined for starters and going from there. It may only be half the problem tho. Poorly adjusted front wheel bearings can add to it as well.


Thanks. Its not particularly bad. Front wheel bearings are on the list :oops: , but can you explain how that would work?
Author:  Scrawny [ Thu Sep 05, 2013 6:05 pm ]
Post subject:  Re: no brake pedal pressure
If there's movement in the front wheel bearings the disc will push the pads back into the caliper, which means there's more fluid movement to get the pads to contact the disc again
Author:  whincup [ Thu Sep 05, 2013 6:10 pm ]
Post subject:  Re: no brake pedal pressure
Scrawn wrote:
How are you bleeding? Manually, vacuum or gravity?



i've used those 1 man bleeders (kept allowing air in around the thread), and i've done the 1 person pump the pedal, the other opens and closes the bleeder. started rear left -> rear right -> front right -> front left. bench bled the MC before fitting that, and that was done before bleeding the rest of the brakes...

and the wheel bearings have only driven up and down the street half a dozen times since they were repacked


mrw82 wrote:
You've got lwb vit calipers on the front don't you? Don't people normally run them on sierras to equalise proportioning when doing rear disks? Given that you still have drum rear your proportioning could be out of whack giving you poor pedal feel.


it can and does get done without going rear disk. the pads are larger and the disks are vented. still, i had the same issue before i went LWB vit calipers...

i've been trying to avoid taking it to a mechanic but i think im out of options now...
Author:  atari4x4 [ Thu Sep 05, 2013 6:13 pm ]
Post subject:  Re: no brake pedal pressure
got a brake specialist near by?

i'd be seeing them before taking it into Tom, Dick & Harry's Mechanical Repairs... my theory is they only do brakes & have probably seen it all before.
Author:  Marko_SJ [ Thu Sep 05, 2013 6:15 pm ]
Post subject:  Re: no brake pedal pressure
Scrawn wrote:
If there's movement in the front wheel bearings the disc will push the pads back into the caliper, which means there's more fluid movement to get the pads to contact the disc again


Ahhh OK. Thanks for your help. Learned new stuff today.

Whincup if you were up here I'd know exactly who to recommend. :(
Author:  whincup [ Thu Sep 05, 2013 6:27 pm ]
Post subject:  Re: no brake pedal pressure
atari4x4 wrote:
got a brake specialist near by?

i'd be seeing them before taking it into Tom, Dick & Harry's Mechanical Repairs... my theory is they only do brakes & have probably seen it all before.


thats the plan, only one locally but they're the ones that have been trying to help me out with it, but i haven't actually taken the car there yet, just parts off it to test/replace/rebuild...

The_Amateur wrote:
Whincup if you were up here I'd know exactly who to recommend. :(


i bought the car from darwin... so it spent a fair bit of time up that way
Author:  Marko_SJ [ Thu Sep 05, 2013 6:36 pm ]
Post subject:  Re: no brake pedal pressure
Is that Joel's maruti? If the brakes don't work I'd bet London to a brick it didn't go where I'm thinking.
Author:  whincup [ Thu Sep 05, 2013 6:44 pm ]
Post subject:  Re: no brake pedal pressure
The_Amateur wrote:
Is that Joel's maruti? If the brakes don't work I'd bet London to a brick it didn't go where I'm thinking.


yep thats the one. he told me before i bought it that it had brake issues but wasnt sure what the issue was...
Page 1 of 1 All times are UTC + 9:30 hours
Powered by phpBB® Forum Software © phpBB Group
https://www.phpbb.com/