yardpro

ill start with the good...

For almost a year now i have had a metallic banging sound when i floored the car or even accelerated hard.

i have not been able to find the issue. Porscheeveret also could not find the problem. It has been driving me crazy and making me not want to drive the car.


i drove it today after the motor mount/oil pan gasket, ground cleaning, brake line replacement.....

I left all the front fender wells, etc off to see if that was the issue. NO dice... Still here..

So i had my son stand beside the road and listen to where it came from... he said the back.. i had thought it was the front, as that is where it sounded like it came from from inside the car..

i pulled the exhaust and heat shields and pulled the plug to inspect the torque converter... one of the bolts was loose. and beat up... HuMMMMMM....
I had my son rotate the rank and saw there was one of the bolts missing...

i stuck my finger down in the hole and VIOLA a bolt was down there... found my issue...

I removed, loctighted and replaed all the bolts with new ones..




so now the bad...... I CANNOT FOR THE LIFE OF ME GET THESE BRAKES BLED.......

there is air some where and i cant find it...

i have a mightyvac and have sucked about a gallon of fluid through... no leaks and still no joy,,

82Porsche928

Do you have a manual? If so, clutch shares the same fluid, problem could be there.

The Forgotten On

You probably have some air trapped in the ABS pump, you need to find some one with a Bosch Hammer or other similar tool you can use to manually actuate the pump while bleeding.

yardpro

LOL... good luck on the hammer.. I live about as far from other 928'rs as possible.

ARRRGGG...

i feel like one step forward and to steps back

SteveG

You don't say (though Brighton asked) if this is a 5 speed and it's not in your sig. If it is, then you need to bleed the master.

Mrmerlin

did you bleed the master first?
The bleeding procedure is bleed the master then LF, RF, RR, LR.
Yes this backwards from what you have been taught but it is in the WSM

That said after bleeding like this a few times around the car,
and you still dont have a pedal then the master cylinder has given up the ghost.

NOTE if your rear pressure bias valve thats screwed into the ABS pump is original ,
replace it when you install the new master .

NOTE I suggest to use ATE Gold fluid ,
unless you have a stash of unopened ATE Super Blue

worf928

There is no option in the Hammer to "manually actuate the [ABS] pump."

yardpro

Sorry for the lack of info.

It is an auto
I have bled the master, and did bleed as per wsm, closest to farthest.

I am using ATE fluid

Going to give it yet another shot today

Leon Speed

A power bleeder is the best tool if you do this alone. Otherwise, have a helper stand on the brake pedal.

jheis

Get a Motive pressure bleeder.

I've had no luck with the mighty vac type bleeders - they suck air past the bleeder threads so you can never tell where the air is coming from.

dr bob

To get vacuum in the system when I got seriously into refilling the system, I used silicone grease on the bleeder screw threads. Dielectric grease is probably the closest to it. You can also use plumbers' Teflon thread sealing paste, a staple product in my grease arsenal.

I ended up doing a section-by-section vacuum-and-fill to get ALL the air out. At some point I'd allowed a little air in during annual flushes, and it gave me a slightly low and soft pedal. It was a chore getting it all out. Nicole mentioned that the factory vacuums the whole system, and draws fluid inro the evacuated system. That's what ultimately worked for me, but I went section by section. I think I had air hiding in the ABS unit, and at a high spot at the T forward of the battery. The effort wasn't exactly fun, but it' was definitely rewarding.

WallyP

On a forum for another type of car, there was a suggestion to go onto an unpaved road and repeatedly activate the ABS to help get air out. Just be certain that the road is level and you know how to drive...

I tried the power bleeder on the wife's Suburban - total failure. The plastic lid for the Chevy master cylinder leaked at 3-4 psi, which was not enough to effectively bleed the system.

Randy V

Who is this Viola of whom you speak?

yardpro

so today i had the wife step on the pedal.... did anout 10-12 times on each pedal... no love....

then i made a uberool vacuum pot. i tool a one gallon jar ad drilled and epoxied two nipples through the lid...
one hose to the caliper nipple the other to an electric vacuum pump for hvac work... figure i am trying to increase the velocity of the fluid, thinking that it will help pull the air out..

i sucked a ton of fluid through and still no love....

my pedal still goes almost to the floor on the first pump then stiffens on the second....

lift the pedal for a second or two and back to the floor.

DRiVING ME CRAZY

dr bob

Vacuum from the master cylinder side of the abs pump. Remove as much air as you can. Then add fluid from the caliper ends. Air bubbles get really big and go up hill faster. Fluid from the ends of the lines at the caliper push the air bubbles towards the vacuum pump. I did this section by section. Then bench bleed the MC so there is no air, purge the lines from the MV to ABS, then connect them at the ABS end. At this point you have no air between the MC and the ends of the hard lines at each wheel. Hold the caliper high as you connect each caliper, push fluid from the MC and bleed each caliper as soon as it is connected. When no air, mount the caliper and go to the next one.

You must get the air pushed out, and it doesn't really like to go downhill on its own, yet normal bleeding expects exactly that. Nicole shared that the factory used vacuum to fill the system initially. That tidbit drove my vacuum refill effort. It's easier to evacuate the system then push any remaining air uphill.