Lowering Bottom Spring Perch

[Captain Obvious]

I got a question... Here's a pic of my donor strut tubes. Note that the right side (left unit) perch spring end points toward the rear of the car, while the spring tip on right side unit points towards the front of the car:

I confirmed on my stock units which are still on my 77 280Z. The spring tip sections of the perches on the left side spring tips point away from eachother (front strut points forward and rear strut points backward), while the right side tubes do the opposite. On the right side, the spring tips are both on the inboard sides.

Question is.... Does it matter at all where the spring tips end up? I'm assuming that there was some simple fixturing reason Datsun put them where they did, but I'm having a hard time coming up with any function reason it would matter where they end up. However, I'm not a suspension guy.

Anyone have any input?

[grannyknot]

On the front it doesn't matter because the hat spins and will always settle in the right place,  the rear I can't picture in my head at the moment but the hat can mount three different positions so one of them has to work.

[Captain Obvious]

And as for the project, I made some progress. Hacksaw with a sharp new blade made quick work of the perches. I was worried that it would be a real chore doing it manually without a machine, but it was actually quite easy:

Turning the strut in the vise as I broke through. And it was quite easy to tell when I broke through as well, so I didn't cut into the strut tube:

Go all the way around and then used a rubber mallet to tap the perch up and off:

Rinse and repeat on the other side and here's where I am right now after grinding off the weld beads:

[Captain Obvious]

5 minutes ago, grannyknot said:

On the front it doesn't matter because the hat spins and will always settle in the right place,  the rear I can't picture in my head at the moment but the hat can mount three different positions so one of them has to work.

Agreed. I just can't come up with any functional reason why it would really matter at all. And the hat in the rear spins as well. No bearing, but the rubber mounting block with the three studs sticking up out of it is independent of the upper perch below it. It's got that goofy hard plastic spacer in there or something? Been a while since I messed with one. Doesn't spin as easily as the front with the bearing, but it should still spin.

Of course, all that said, My OCD will force me to put the perches back on the same way they came off. Lower, but same rotational orientation.

[grannyknot]

5 minutes ago, Captain Obvious said:

 I just can't come up with any functional reason why it would really matter at all.

The factory probably used the same jig for welding up L & R struts so the perch would be same on both, perhaps.

[Captain Obvious]

I was thinking the same thing. Manufacturing fixturing only. That, and you can't tell 70's Japanese welder on the line "It doesn't matter... Put it anywhere." He would likely self combust from the internal ambiguity.

And on a related note, I found a pic of the plastic spacers they use in the rear (instead of the bearings). I think I might make some steel replacements to use when I put mine back together. Might be able make them a little thinner than the originals for more lowering:

[Captain Obvious]

So today's question... Does anyone have a good manufacturer and specific details for a bellows set that fit's well on the 280 struts? I bought a pair of KYB's couple years ago when I was into the struts last time and they were too big. Couldn't get them to fit right.

No surprise, but the bellows that came in my donor strut assemblies were worn out and need to be replaced. Anyone got something that really does fit well?

[grannyknot]

I haven't found good ones yet, I've bought several sets over the years and they are usually stiff plastic that don't seal at the bottom.  It's a part that is ripe for reproduction.

[Captain Obvious]

Crapsticks. That's not the answer I wanted. I really thing the original design (with the bellows and the retaining ring at the bottom) is pretty slick.

@AK260, you mentioned in another thread that you were using the bellows from the front of a dirt bike or something? How did that work out?

[AK260]

Crapsticks. That's not the answer I wanted. I really thing the original design (with the bellows and the retaining ring at the bottom) is pretty slick. [mention=32052]AK260[/mention], you mentioned in another thread that you were using the bellows from the front of a dirt bike or something? How did that work out?  

 

 Sorry to see you have the same issue Captain. Totally agree on the original design being elegant. 

If you’re not bothered by originality, the classic BSA motorbike ones worked perfectly and look all the money - way better than the RockAuto ones. I had to trim the edge off one end to help it over the spring top-hat lip without covering the drain holes (a tight fit even with the originals). The dimensions on the other end are tight enough over the strut tube body (late 260z) that I could have gotten away without the clip. I did add the clip regardless but it’s not hidden like on the originals gaiters.

 

 

Here’s the link. Let me know if you can’t find them or anything else suitable state-side and I will get some to you.

 

https://www.classicbikeshop.co.uk/bsa-fork-gaiters-42-5320.html

 

 

Here are some dimensions for comparison ...

 

 

 

[AK260]

One other thought, can these guys help source for you locally?


https://www.classicbritishspares.com/

[Captain Obvious]

AK260, thanks much for the additional info. I'll look into those to see what I can find on my side of the water.

And on a related note... The 74 FSM says the strut tubes OD is 2 inches (50.8mm). After that, (in later years manuals, they greatly reduced the amount of detail about the suspension members. Starting in 75, they stopped listing the OD of the tubes as well as much of the info about the corner springs.

Why is this related? Because all the tubes I have here are from various years of 280's and they are all 55mm OD (2.165 in), not 50.8mm. I'm assuming this was part of the beefing up of the suspension stuff that occurred for the 280. Unfortunately none of this is documented in the manuals, but it needs to be taken into account when looking for things like those strut tube bellows / gaiters.

It also matters when you're trying to size split collars to use as temporary spring perches to hold the springs in place for locating. If you buy 2" collars, they won't fit: