521 rear wheel cyl

[banzai510(hainz)]

i was replacing a parkn brake cable and find out the wheel cyl has slow leak. Went to o rileys said get end of month. I found some japan old stock on ebay. Has anybody tried the thailand made units? This is 3rd time swap. This 521 is a pain. Wish i got a 510wagon so much ezer to maintain. So any kingpin 521owners get spares when you can so your not waiting weeks for a simple part

https://www.ebay.com/itm/306039749770?fits=Model%3A521+Pickup|Make%3ADatsun&_skw=datsun521+rear+wheel+cylinders&itmmeta=01K0FGFQ6BJN9WJSRGB0QA7S3R&hash=item474163fc8a:g:Rg4AAOSwHdBnhfTo&itmprp=enc%3AAQAKAAABAFkggFvd1GGDu0w3yXCmi1ej40lf6ouO8zsWhc94RehnilHr7GNl1RaaQZnBfpxQRnr3jQ6QwMlb25z%2F7RwJtSOElxa3wKTfNxqFbyrELuVh9DXvbx7WiD5reIrHeW%2F6NutXzb53xVo3U0mitiqrPexCMXTUbzgFOCOmbNGrJEfI0sSYmqqDnUHPfUxX9a2e%2BS3Khr%2Bi3%2Fel07HrkAPKNLthpwBnHnHcPDbQ9KiJDYVvnfp5fKb56l9sXpd1f98QH%2FKlVNfSRZaUUPJF%2BMxtbYIs%2FGnpLbB7%2FCoj0d4QPzux9SqMqqutQBXxJ3q13YCOGWLhn%2FaA7fT1YTpOZCwgHGE%3D|tkp%3ABk9SR6jzvvCDZg

Edited July 18, 2025 by banzai510(hainz)

[datzenmike]

I hate these days. Back in the '70s you could buy the rubber seal parts for like a dollar and rebuild them yourself. Scour the bore with some fine steel wool, wash and dry and assemble. Quoted over $500 to take our lift truck to the shop and replace the leaky wheel cylinders. I replaced the 3/4" seals with those from a '60s Rambler for about $3. I did once get a Nissan rebuild kit for Datsun slave cylinder, now most likely NLA, for $12. New bleeder with rubber cap, new seal, and new rubber dust boot. 

[Slow Loris]

7 hours ago, banzai510(hainz) said:

tried the thailand made units?

 No just the Rockauto selection which seems ok if doesn’t leak immediately out of the box. Is that what you been using?
 

datsun-roadster-parts.com sometimes has nos 521 brake stuff that is comparable in price to that Thailand eBay one. 
 

 

[datzenmike]

I would definitely take them apart and check for left over machining chips, then lube seals with brake fluid and assemble again. Recently had to replace my 710 slave. It was fine but the seal was not like the very firm rubber from decades ago. It was floppy like an eye contact lens.  

[banzai510(hainz)]

i order old stock japan ebay. Centric brand on ebay has pairs for abt 60-65bucks but no bleed and crushwasher. Do most use the old crushwasher?

[Slow Loris]

Oh I see yeah that banjo fitting with bleeder and the inlet is sure hard to find. I had the same problem and got some used ones from a parts guy and took the fitting off and swapped it to my existing assembly. When I had this issue I found some stuff like these https://southwestspeed.com/products/301-0877?gQT=1 not sure if they fit in exactly but could be an option if cylinders are good but your bleeder is bad.

Me, I replaced all the washers i think it helped a lot there was plenty of little brake fluid crusties on there beforehand from a little seepage.

 

[ggzilla]

I always re-used the washers. If crusty you can run it flat along a file to clean it up. Or just take it to NAPA and match up some new copper washers

14 hours ago, banzai510(hainz) said:

Do most use the old crushwasher?

 

People seem satisfied with Datsun rubber parts from Thailand. They had many car assembly plants there, and presumably supplied many parts for Nissan. Like Japan, I'm sure there are a few lower-quality suppliers, but on the whole they seem well regarded

[banzai510(hainz)]

Well I swapped the Japan made rear wheel cylinder in after replacing the Parking brake cables that were broken for years.  I was short about 1.5 inches so I made a plate and put 2 bolts thru them and now they seem to work( a small turn buckle was still too long). On final inspection I notice my Belltech lowering blocks were off like a 1/4 on rear driver side. I said fuck Im tired of crawling around around. Said Fuck it I ordered another set of 3in 2deg Belltech part# 6202 blocks. While waiting for those I took the blocks off to find the pass side stub was sheared off and the driver side almost sheared off.  So on 521s always do a inspection of these parks and grease the Kingpins and driveline 

[ggzilla]

Do you mean this pin was sheared off? I wonder if the locating pin is replaceable, but how would you get it out?

[banzai510(hainz)]

yes it was sheared off the other was just hanging on like a hacksaw was cutting it. guess axle was moving around and stressing the pin. Instructions say 80pounds for torq on the bolts/nuts(should always ck these every year anyway.

doesnt seem the pins are steel but cast. I have to look again before I throw them away

 

I bought new blocks fits perfect now.