Wilwood 1 Inch MC failed. Trying 7/8 MC with Maxima Rear Calipers

[Miles]

1972 240Z SBC

Stock front brakes.

Maxima rear calipers

280Z booster

Hawk HP pads

 

For the  third time, a new Wilwood 1 inch master cylinder has  leaked past the rear seal soaking the booster. I had a stock 7/8 inch MC on hand so I thought I would try it . Others have reported that they use a stock 7/8 inch MC with 280ZX rear calipers and that the pedal travel is long and a bit squishy. But since I had the 7/8 inch MC I tought I would give it a try.

 

I removed the residual check valve from the rear brake outlet port of the stock MC.  The booster push rod was set right and the reaction disk was epoxied in place (I have lost two). I now make reaction disks by cutting the ends off of rubber stoppers.

 

I bench bled the MC and used a power bleeder while moving the Maxima calipers around to get the air out. Re-bled it after sitting overnight using speed bleeders so I think I got all of the air out.

 

I  just got back from a test run with the stock MC/Maxima set up. Not good. The pedal travels about 3/4 the way before effective braking starts and, as others have noted, the pedal feels squishy. I am not comfortable with it, so I'll order another Wilwood 1 inch MC and just plan on checking it often.

 

For the Maxima calipers, the stock MC volume is too small and the 1 inch MC has the right volume, but is  too stiff.

 

Actually, the 15/16 MC is probably the best compromise, but NLA.

 

In my Hybrid search I found at least three members who use the 7/8 inch  MC with stock fronts and 280ZX/Maxima  rear calipers and are happy with the pedal travel and feel.

Edited August 3, 2013 by Miles

[holyshiet]

I just installed maxima rear brakes with the wilwood 1" MC.  Remember that you have to adjust the push rod when you change master cylinders.  I had a 73' and I couldn't for the life of me, so I had a machine shop shave off some aluminum (from the rectangle aluminum adapter with 4 holes) for the wilwood to work properly.

 

Lastly, the maxima calipers were a pita to bleed.  I ended up taking the calipers out, flipping the bleed nipples so it's straight up, and bled them there (You can use a block of wide block of wood to simulate the disks if needed.  Then reinstall and press the pedal til you get contact with the disk.).  If the pedal is squishy, there is definitely still air in there.  It took me about 3 bleeds to get all the air out.  Then the pedal felt firm like expected.

 

 

1972 240Z SBC

Stock front brakes.

Maxima rear calipers

280Z booster

Hawk HP pads

 

For the  third time, a new Wilwood 1 inch master cylinder has  leaked past the rear seal soaking the booster. I had a stock 7/8 inch MC on hand so I thought I would try it . Others have reported that they use a stock 7/8 inch MC with 280ZX rear calipers and that the pedal travel is long and a bit squishy. But since I had the 7/8 inch MC I tought I would give it a try.

 

I removed the residual check valve from the rear brake outlet port of the stock MC.  The booster push rod was set right and the reaction disk was epoxied in place (I have lost two). I now make reaction disks by cutting the ends off of rubber stoppers.

 

I bench bled the MC and used a power bleeder while moving the Maxima calipers around to get the air out. Re-bled it after sitting overnight using speed bleeders so I think I got all of the air out.

 

I  just got back from a test run with the stock MC/Maxima set up. Not good. The pedal travels about 3/4 the way before effective braking starts and, as others have noted, the pedal feels squishy. I am not comfortable with it, so I'll order another Wilwood 1 inch MC and just plan on checking it often.

 

For the Maxima calipers, the stock MC volume is too small and the 1 inch MC has the right volume, but is  too stiff.

 

Actually, the 15/16 MC is probably the best compromise, but NLA.

 

In my Hybrid search I found at least three members who use the 7/8 inch  MC with stock fronts and 280ZX/Maxima  rear calipers and are happy with the pedal travel and feel.

Edited August 4, 2013 by holyshiet

[Miles]

Another member also suggested pulling the Maxima  calipers, point the bleeder up while shaking  and moving the caliper around.  I'll give it a try.

 

Thanks

[seattlejester]

To be honest I find even my 15/16th MC is a bit squishy in the beginning of brake travel with my maxima rear calipers.

 

I think you can also get away with jacking up the rear a bit to get the bleeder screws lined up and tapping it with a rubber mallet to dislodge any trapped bubbles.

 

Making sure your brake booster hose is not collapsing and the one way valve is not sticking might help a bit. I know mine was visibly flexing and I wouldn't get any brake travel until the bottom with that setup. 

 

Adjusting the rod is definitely suggested, the first inch or so of my travel is uninspiring, but I moved the engagement point up from the bottom quarter of travel up to the upper half or so which makes the brakes feel a lot better.