75 280Z Front Suspension Work, Brake Upgrade and 15x7" Konig Rewinds

[HusseinHolland]

Drove the car to work again the past couple days. It has a vibration in the front end that varies, in other words it doesn't always come on at the same road speed, and will go away when the stars align (it seems). The only thing I haven't replaced are the inner tie rods, however there was no discernible play in them. When it happens, the steering wheel vibrates pretty harshly, and there is a 'chatter' in the steering column, it seems.

The only thing that I couldn't find a spec on is the torsion rod bushing end nut - I just made them 'snug' - about 4-5 exposed threads outside the nut. Does anyone have a spec for that? I didn't find it in the FSM/Front Suspension section .

Any other tips? Obviously I'm going to have to recheck the inner tie rods. Also wondering if just increasing the wheel & tire sizing has made it more susceptible. I did much the same on my '80's Fiat (with similar suspension design/layout) with no adverse effects, so that doesn't really seem to make sense.

[Patcon]

Aren't you running wheel spacers up front?

[Racer X]

On 5/29/2023 at 5:25 PM, HusseinHolland said:

Finally got back to the brakes. I bought the ZcarDepot kit, which comes with no directions. I didn't realize that the supplied hose is intended to replace both flex & rigid lines, it didn't appear long enough. Besides that, the back plates have to be modified to clear the larger Toyota S12 caliper. 

I had cleaned out the old grease from the hubs, and repacked the wheel bearings in preparation for reassembly. So, I filled the hubs with new bearing grease as per the FSM, and installed the inner bearings & grease seals.

I also found I never received the 8 longer bolts with the brake kit. Thankfully I had extra bolts from a CEIKA brake kit. Rotor spacer in place. CEIKA bolts. 

Vented rotors bolted to hubs.

Single hose to replace original hoses

Hose installed into caliper first, to prevent twisting or binding the hose

Modifying the back plate. Sections removed

 

I didn't want to leave cut edges on the back plate, so I reduced & welded the folded edges back on

 

Cleaned  up, primed, painted & installed

Hubs & rotors installed, bearings adjusted. Longer studs installed for the Konig wheels

Nice touch on the grease caps, oring seal

Pads & hardware installed. The outer pad didn't have the hole for the damper spring, had to drill it out

Just need to bleed the brakes

Looks nice, you are doing some great work on this Z.

I did this mod back before anyone made a “kit” for it. Sourced the Toyota 4x4 calipers and 300ZX rotors from the local parts supplier, made a drawing in CAD for the spacers and had a local machine shop cut a pair from 7075 T1 aluminum, picked the longer bolts at the local specialty bolt supplier.

It was on my race Z, so I didn’t use the backing plates, instead custom building aluminum cooling ducts to direct air to the center of the rotors and also to the calipers. I made up my own stainless braided Teflon hoses with 37 degree JIC fittings and all the hard lines from stainless steel tubing.

Works awesome, brakes that last all weekend at a race meet and don’t require bleeding after every track session.

 

[Patcon]

1 hour ago, Racer X said:

Looks nice, you are doing some great work on this Z.

I did this mod back before anyone made a “kit” for it. Sourced the Toyota 4x4 calipers and 300ZX rotors from the local parts supplier, made a drawing in CAD for the spacers and had a local machine shop cut a pair from 7075 T1 aluminum, picked the longer bolts at the local specialty bolt supplier.

It was on my race Z, so I didn’t use the backing plates, instead custom building aluminum cooling ducts to direct air to the center of the rotors and also to the calipers. I made up my own stainless braided Teflon hoses with 37 degree JIC fittings and all the hard lines from stainless steel tubing.

Works awesome, brakes that last all weekend at a race meet and don’t require bleeding after every track session.

 

How did you handle F/R bias? Are you still running stock drums in the rear?

[Racer X]

4 hours ago, Patcon said:

How did you handle F/R bias? Are you still running stock drums in the rear?

Wilwood 2 piston calipers and 280ZX solid rotors in the rear (no parking brake), and a Tilton dual master cylinder pedal assembly with adjustable balance bar, and asymmetrical master cylinder sizes (sorry, I don’t recall the diameters, I’ll check when I get a chance).

[Yarb]

Here is what worked for me.

https://technotoytuning.com/nissan/280z/z-rotor-spacers-s12w-4-piston-toyota-caliper-conversion

[Captain Obvious]

23 hours ago, HusseinHolland said:

The only thing that I couldn't find a spec on is the torsion rod bushing end nut - I just made them 'snug' - about 4-5 exposed threads outside the nut. Does anyone have a spec for that? I didn't find it in the FSM/Front Suspension section .

Torque spec for the torsion rod end nut - Page FA-2 of the manual says 33 to 40 ft-lbs. Basically, you should compress the rubber to the point where you have bottomed out against the metal sleeve that runs through the center and then torque to hold it there.

Oh, and not totally sure, but it looks to me like you have the big washers on the torsion rod bushing installed backwards. They should have the convex side towards the rubber. Counter-intuitive, but that's the way they want it.

Should be like this:

 

Edited June 17, 2023 by Captain Obvious

[HusseinHolland]

On 6/16/2023 at 11:18 AM, Patcon said:

Aren't you running wheel spacers up front?

I am. 

23 hours ago, Captain Obvious said:

Torque spec for the torsion rod end nut - Page FA-2 of the manual says 33 to 40 ft-lbs. Basically, you should compress the rubber to the point where you have bottomed out against the metal sleeve that runs through the center and then torque to hold it there.

Oh, and not totally sure, but it looks to me like you have the big washers on the torsion rod bushing installed backwards. They should have the convex side towards the rubber. Counter-intuitive, but that's the way they want it.

Should be like this:

 

Many thanks for the clarification. I do indeed have the conical washers set to 'cup' the bushing, so I will take it apart & properly torque them. Makes sense the bottom it against the sleeve. Hopefully that accounts for my vibrations - I must have excess fore/aft movement as it is.

EDIT - putting it together with the suspension hanging at a pretty acute angle, the bushings don't seem nicely aligned with the seats, so I think I'll wait to torque them when it's on the ground, where the angle is in it's rest state. I think I'll also switch out the forward one for the poly, as you have in your pic.  

 

I tested positive for COvid yesterday, symptoms are pretty harsh this time. Figured I better reply while I have a window of clarity.

 

Presumably the nut icon labelled A - H are the indicators of torque spec - I didn't get it as the legend at the bottom has gibberish inserted

Edited June 18, 2023 by HusseinHolland

[Patcon]

Hate it on Covid.

Ive had it a couple of times. First time was the worst.

Several members have had vibrations from less than perfect spacers

[Captain Obvious]

The issue with the gibberish in the manual... The manuals were scanned to PDF on a flat bed scanner and OCRed (Optical Character Recognition). Not sure why, but the OCR process for the 75 manual (and only the 75 manual) didn't do so well. If you look at the same page FA-2 in the 76 manual everything makes sense.

One last thing I think I see on your pics is that there should be a smaller flat washer on both outside ends of the larger washers. Doesn't look like you have one of those on the forward side of your car. Looks like you have the big domed washer right up against the shoulder on the T/C rod.

Good luck with the covid. I don't think I'm ever going to be the same. I think I'll be OK, but different.

 

[Zed Head]

Here's a shot of a crusty old, that looks original, 76 compression rod end.  Picture 187.

https://bringatrailer.com/listing/1976-datsun-280z-59/

Edited June 18, 2023 by Zed Head
grammar fix attempt

[Racer X]

On 6/17/2023 at 3:12 PM, HusseinHolland said:

 

I tested positive for COvid yesterday, symptoms are pretty harsh this time. Figured I better reply while I have a window of clarity.

 

 

Covid eh?

That sucks.

I thought we were pretty much past that unpleasantry.

Get well soon.