Another Grand (+ 1/2) Down The Tube...

[_Ryan_]

try nissco in bayswater, helped with my 1600

[Factory 5]

try nissco in bayswater, helped with my 1600

they know what they are doing.....

good service too!

[coupe72001]

they know what they are doing.....

good service too!

Nissco are a long train ride home for me, but if they sort the car it'll be more than worth it, so thanks for the recommendation. Im pulling my hair out at the moment because my old workmate who has the only set of spare keys to my car seems to have fallen off the face of the planet! Looks like Ill be wiring up my spare ignition barrel this weekend!

[Factory 5]

Nissco are a long train ride home for me, but if they sort the car it'll be more than worth it, so thanks for the recommendation. Im pulling my hair out at the moment because my old workmate who has the only set of spare keys to my car seems to have fallen off the face of the planet! Looks like Ill be wiring up my spare ignition barrel this weekend!

or a hidden start switch...

[coupe72001]

or a hidden start switch...

Its all good. Swapped the ignition barrel and did the rear brake pads (again) this weekend and both exercises went really well. Am also now very confident that the coil setup is all kinds of wrong. Maybe there is a light at the end of the tunnel!

[coupe72001]

Its all good. Swapped the ignition barrel and did the rear brake pads (again) this weekend and both exercises went really well. Am also now very confident that the coil setup is all kinds of wrong. Maybe there is a light at the end of the tunnel!

G'h! How irritating. Changing the rear brake pads bought me all of 35kms of blissful silence before the grinding noise came back.

I'll be picking up an "ICE" coil and leads tomorrow. Fingers crossed that helps get the engine running right.

[aarc240]

G'h! How irritating. Changing the rear brake pads bought me all of 35kms of blissful silence before the grinding noise came back.

Has the brake master cylinder been changed at some point?

Alternatively, was this car fitted with a drum brake rear end originally which has been upgraded to disc?

Does it wear the rear pads quickly as well as making lots of noise?

Wear evenly across the whole pad (ie not thin on one edge etc)?

What you are describing makes me suspect that you have a drum brake type pressure maintenance valve in the rear brake circuit.

Could even be the wrong proportioning valve.

What either can do is prevent the rear pads returning to rest position correctly after each brake application. The problem is that the failure to fully return is cumulative so all seems good to start with but the pads gradually apply more and more load on the discs.

It doesn't do much good for performance either so I'd sort this out before chasing that engine gremlin much further.

[coupe72001]

Has the brake master cylinder been changed at some point?

Alternatively, was this car fitted with a drum brake rear end originally which has been upgraded to disc?

Does it wear the rear pads quickly as well as making lots of noise?

Wear evenly across the whole pad (ie not thin on one edge etc)?

What you are describing makes me suspect that you have a drum brake type pressure maintenance valve in the rear brake circuit.

Could even be the wrong proportioning valve.

What either can do is prevent the rear pads returning to rest position correctly after each brake application. The problem is that the failure to fully return is cumulative so all seems good to start with but the pads gradually apply more and more load on the discs.

It doesn't do much good for performance either so I'd sort this out before chasing that engine gremlin much further.

Mate - that is an eye-poppingly useful reply!

I should have added some info before I started whining about the brakes.

You are correct in guessing that the entire rear end (280zx series 2) is disk as opposed to drum, with overhauled calipers, machined disks and fresh brake pads. I have also upgraded to a 280zx (1 inch from memory) master cylinder. BUT I never even considered the pressure maintenance valve or proportioning valve. Actually I can't even remember if I used the C210 or 280zx valves, not knowing exactly where they are even located on the car.

At a glance the pads have been wearing evenly, but the problem having a "cumulative" effect sounds all too familiar.

Finally, my auto electrician (of all people) is convinced that there is something gravely ill with the rear bearings/axle. I assumed that seeing the grinding disappears with brake pedal pressure and that the noise doesn't increase when cornering in one direction that it had to be a brakes issue - but hopefully it may be something as simple as a nasty bearing.

In short, if a bearing change doesn't sort the problem Ill start hunting for the correct valves.

Also, said auto electrician fitted my fancy new coil today, then called to say that the taco had stopped working and he didn't know why. Worrying.

Anyway, fingers crossed,

D

[coupe72001]

My auto electrician got back to me on Friday afternoon. The new coil is all wired up correctly and the car runs - but don't know how she'll hold up on a proper test run yet. He also pulled of a wheel and had a play around and is convinced that something the rear right hub assembly has gone to hell and is the source of all my grindy woes.

Does anyone have a rear right suspension arm with an intact hub assembly from a 280zx that I can poach? I don't actually need the whole arm, its just a lot easier to grab it as a unit rather than pulling the hub to pieces. If not Ill start sifting through the wreckers from Monday morning.

[Matty T]

BUT I never even considered the pressure maintenance valve or proportioning valve. Actually I can't even remember if I used the C210 or 280zx valves, not knowing exactly where they are even located on the car.

When you do decide to check (and it is a pain in the arse because you have to crack the brake lines and then bleed the entire system again), here is what to look for:

The residual pressure valves are located behind the adapter nuts where the brake lines screw into the master cylinder. Once you undo them, they are seated inside.

In the picture, the one on the left is from a disc-braked end, and the other is from a drum brake. Notice the two slots on the left one - they let the pressure bleed back into the master cylinder, whereas the right one does not. A small amount of pressure remains in the line (the rear line in this case) and that keeps the drum brake slave cylinders pressing out just a little, ensuring that the shoes are ready for action. if the pressure wasn't there, the shoes could "chatter" and thus you would have a "long" pedal on the first brake application.

If you put disc brakes on and do not either a) put slots in/put the right R.P. Valve in, or b) remove it completely, then you could end up with a caliper "dragging".

Sorry, I can't help with a rear arm.

[coupe72001]

Thanks so much Matty, that's a hugely useful reply and now I don't feel half as despondent as I did a week ago. If a new hub doesn't quiet things down in the back Ill know exactly where to look next.

Thanks again.

Drew

[STATUS]

the fuel is vapourising in the line after the pumps, quite common. (vapour lock) how close is your line to the exhaust?

[coupe72001]

the fuel is vapourising in the line after the pumps, quite common. (vapour lock) how close is your line to the exhaust?

The fuel line is on the opposite side of the car to exhaus, right up until it reaches the carbies, which are on the same side as the extractors. Funnily enough, often I see the (metal by this point) fuel lines wrapped up in a heat-resistant bandage on 240/260z cars... maybe there is a good reason for that.

Still, I did the first test run today with the new coil, and it seems to have made a huge difference; she's not choking up at all. So that's a really promising beginning to sorting out some of the bugs. Can't wait to try new hubs (or valves) to see if the grinding noise goes away.

[Factory 5]

i know of 2 280zx in local wrecking yards (kilsyth pick a part and ringwood/heatherdale rd pick pay & go)

both seemed to have semi-complete rear ends....no motor/box/diff/ or any important good stuff!

i can check MAYBE check after work tomorrow, but depends on how much work!

[Rhys1600]

I've only ever had vapour lock / fuel boiling dramas with my dattos when combined with stinking hot weather.

[coupe72001]

Maybe the extractors have increased the under-bonnet temperatures some, but yeah, the problem seemed more noticable when it was hot, or when I got stuck in traffic. I had a really long run last night and the problem wasn't there so thats a great sign. I guess the next stinking hot day will be the real test.

Also thanks Mags - Ive got a mate who may be able to sort me out with the suspension on the weekend, but if it goes pear-shaped Ill shoot out to Pick a Part and check out what they have there. A couple of 280zx's is promising - I'd be surprised if anyone had pulled out the rear suspension arms!

[coupe72001]

Had a bit of a set back (no surprises). My mate who was going to help me with suspension arms has been hospitalized, so I hit both Pick-pay n go places and some bugger has got in there before me and stolen the rear suspension! I found a new (as in just arrived) 280zx at Centre Rd Springvale, but the hub assembly and drive shafts were a different design to mine. I had assumed that the rear suspension set ups were all much-of-a-muchness. D'oh!

In the end I handed over the suspension arms to a local mechanic and have asked him to pull apart the hubs to see what he could find. Hopefully I'll have them back on the car soon and everything will run smoothly from then, unlike my flatmate's 350 Chev powered range rover which I borrowed and blew up yesterday. Looks like I killed the transfer case. Oops.

[Factory 5]

DAMN V8's BUST EVERYTHING!

even ghost's V8 lexus powered cressida seems to like bustin suff too!

the kid that i bought my L20et from dropped in a 5 liter vl engine in his HR30... broke just about everything then!

did the 280zx still have the engine in??????

[coupe72001]

No - the 280zx was complete, except for the engine and rear brakes. I poached the brake master cylinder as a spare seeing Im prone to blowing those up.

The Range Rover episode was a bit of a travesty. Bought on ebay, we picked it up Monday morning and I had blown it up by Monday evening. Had to go home with the RACV. It was hilariously quick for such a big wobbly truck though, till something went POP!

[aarc240]

The info on the residual pressure valves is good but don't leave it out of the rear circuit altogether.

You can't (easily) modify a drum brake residual pressure check valve to a disc brake version as they both provide residual pressure in the lines - just different amounts to suit the different brakes.

Drum brake circuits vary in residual pressure according to the original design, commonly 10 psi for Australian & American, either 7 or 10 psi for Japanese and anywhere from 2 to 15 psi for the various weird Pommie stuff.

As Matty described, it stops knock-back of the shoes and is dependent on what sort of return springs etc are used in the design.

Disc brakes are pretty much universal at 2 psi.

That is JUST enough to stop pad knock-off in normal use so that you don't get that dreaded long pedal.