help bleeding front brakes (280z master cyl.)

[Friscolada]

I have datsun 510, i was upgrading from 3/4 to 7/8. I have 280zx front brakes. My rear brakes bleed just fine, but front wont bleed at all. Master reservoir not moving any fluid down, i open bleeder at reservoir and no fluid coming out.

 

280z master cylinder is brand new

 

Any ideas?

thanks

[datzenmike]

They can be bad from the box.

 

Did you 'bench bleed' it?

 

Loosen the line to the rear of the master cylinder marked F. Gently pump brake, anything come out?

[john510]

Get some clear tubing that fits on the bleeders at the master cylinder.Make it long enough to go from the bleeder into the fluid resevoir.Make sure resevoirs are full.Crack both open and start pumping.You should eventually see fluid and air going through the tubes and then nothing but fluid.I had the same problem and it took about ten minutes of pumping the pedal to get the air out.

[Friscolada]

i will go try see if any ideas work, will be back in bit with report on failure or success.

[Friscolada]

1. so we pumped it no fluid movement for front brakes. (10 min)

2. Lose the line and pump it no fluid going down what so ever, took the line off and pumped it.

 

Bad Master Cylinder?

 

Would it effect if use rod of 510 and installed it into 280z?

[thisismatt]

Make sure there is a little slack/play in the rod when the pedal isn't pressed.

[john510]

1. so we pumped it no fluid movement for front brakes. (10 min)

2. Lose the line and pump it no fluid going down what so ever, took the line off and pumped it.

 

Bad Master Cylinder?

 

Would it effect if use rod of 510 and installed it into 280z?

Yes,the 510 push rod is too short.

[Friscolada]

Yes

 

Thanks for help, im going to get replacement then. :thumbup:

[Friscolada]

Make sure there is a little slack/play in the rod when the pedal isn't pressed.

 

yes i had some play, i gave a lot of play, took most of it out... nothing made a difference

[macgyver]

Any update? I'm in the middle of doing the same swap right now and I'm not sure if I can use the stock 510 push rod? Do I just lay it on place and take out the slack? Then need to bleed everything. Any insight would be great.

 

[CableDroid]

Having similar issues with a brand new 7/8" master. Did you ever get it figured out?