'72 Wagon: Bueiz

Post by **bueiz** » 18 Jun 2014 08:36

We worked on thee brake system for 2+ hours yesterday evening, doing about 3 cycles of the "pump-up" method at the Master Cylinder and all 4 corners, with no significant improvements.

I'll probably dive into getting a new MC or a rebuild kit, next.

If the new MC doesn't work I'll be going thru and swapping the entire brake system. Anyone have any recommendations for brake line (hard and flex) and valve replacements? I see the brake line kits on eBay, but I don't know if they're any good.

Thanks, everyone, for all the help and input.

Post by **bueiz** » 18 Jun 2014 08:54

Just some teaser photos.

I like the height of the front and need to work on bring down the rear some. I feel like the wheels in the back look too small, after tweaking the drop I'll see if I still feel that way.

Post by **two_68_510s** » 18 Jun 2014 09:00

Nice. When it is lowered, it seems like bigger wheels would look better.

James · Post by **James** » 18 Jun 2014 09:57

More rubber aspect would help too.

Post by **okayfine** » 18 Jun 2014 10:28

James wrote:More rubber aspect would help too.

This. Wheel size is at least 15", more than enough to fill a 510 arch with the appropriate rubber. 50-series or above, the tires fitted look like 45-series?

Post by **okayfine** » 18 Jun 2014 10:30

Brake line thread here:
viewtopic.php?f=29&t=26600

If there's a problem besides air, it's probably in the BMC. I'd definitely suggest going through that and/or swapping it before tearing apart the rest of the brake system.

JordanTr · Post by **JordanTr** » 18 Jun 2014 13:08

okayfine wrote:
James wrote:More rubber aspect would help too.
This. Wheel size is at least 15", more than enough to fill a 510 arch with the appropriate rubber. 50-series or above, the tires fitted look like 45-series?

+1 looks sweet still though! I had 195/45/15 and it was a lil small for my liking but they were just borrowed rims n tires.

Keep up the good work.

Post by **bueiz** » 18 Jun 2014 13:50

The tires are 50-series, but do look like a lower profile.

I ended up going with 15x6 Rotas since I was skeptical about the fitment up front and I think the 6-inch wide wheel up front is the widest I can do with this front end coil over set-up. I'm okay with the fitment of the wheel/tire combo up front. I may need to opt for a wider wheel in the back at some point.

okayfine wrote:
James wrote:More rubber aspect would help too.
This. Wheel size is at least 15", more than enough to fill a 510 arch with the appropriate rubber. 50-series or above, the tires fitted look like 45-series?

Post by **bueiz** » 11 Jul 2014 20:05

I'm hitting you guys up again to see if you had any more thoughts on my brake issue.

I performed the pump up method several times, tried it on a few different days, with different pumpers. Initially I had a the 15/16" 280ZX master cylinder; but, after what it seem to be several failed attempts I purchased another master cylinder.

I ended up buying a 1-inch Wilwood master cylinder. Modded it so it would fit the Datsun fastener pattern, and I swapped out its outlet fittings with the fittings from the 280ZX master cylinder so that I could maintain metric (10mm x 1) brake line fitting connections (Wilwood comes with 3/8"-24 outlet fittings).

I'm back to doing the pump up method with the new master cylinder, but no luck as of yet. I do get feedback with 2-3 pumps vs. the 15-20 pumps with the 280ZX MC. I assume because it's a larger diameter MC.

I'm rackin' my brain trying to figure this out. I've seen posts about gravity bleeding, but the posts are usually about cars with brake boosters (newer cars). Does gravity bleeding work for our cars? Also, I'm working under a carport and the carport has a very slight incline. So the way the car is jacked up on stands the car is tilted over on its drivers side. I'd probably say it's on a 10-deg tilt. I'm grasping at straws over here...

Post by **okayfine** » 12 Jul 2014 07:10

No further real ideas. You could try bleeding with a MityVac, pulling from each bleed port. Typically this is recommended when you have one person to bleed brakes - it's not strictly all that different from what you're using.

Have you also swapped out those rear wheel cylinders you mentioned? Are you still getting air bubbles when bleeding?

Post by **510wizard** » 13 Jul 2014 06:55

You can also get one of these and push fluid from the wheel cylinders to the master.
http://www.amazon.com/Phoenix-Systems-2 ... B00GRV800S
Think of it this way, air wants to raise in fluid, so pushing the fluid from the lowest point (wheel cylinder) in the system to the highest point (master). The air will raise to the masters reservoir.
http://www.youtube.com/watch?v=1LVyA_3lOmM

Post by **bueiz** » 14 Jul 2014 09:47

Thanks for the suggestions guys.

I did install new rear wheel cylinders. I have fluid at all four corners, the fluid is clean and bubble free.

I did get a PM over the weekend suggesting that I may have installed the calipers upside down. And, although a little embarassing to admit, that may be my issue.

I'll have to verify when I get home after work.

Post by **okayfine** » 14 Jul 2014 12:29

If the bleeders are at the high point, then you're good, but if they're not then that's definitely an issue. I'd actually done the same, on purpose, in order to get the e-brake pulls in line with the OE routing. But, yeah, then I had to pull the calipers and rotate every time I needed to bleed the system.

Post by **bueiz** » 14 Jul 2014 20:54

The bleeders were below the hoses, oops.

I swapped the calipers and it stops on a dime.

Post by **bueiz** » 14 Jul 2014 20:55

...and then...

The 510 Realm

'72 Wagon: Bueiz

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