Jump to content
We Need Your Help! ×

IGNORED

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


Recommended Posts

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.

Link to comment
Share on other sites


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.

PXL_20230529_161258472.jpg

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. 

PXL_20230529_161330626.jpg

Vented rotors bolted to hubs.

PXL_20230529_163542894.jpg

Single hose to replace original hoses

PXL_20230529_164936670.jpg

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

PXL_20230529_193303077.jpg

PXL_20230529_174833034.jpg

PXL_20230529_193651857.jpg

Modifying the back plate. Sections removed

PXL_20230529_174924219.jpg PXL_20230529_174932278.jpg

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

PXL_20230529_183754794.jpg PXL_20230529_184306065.jpg

Cleaned  up, primed, painted & installed

PXL_20230529_194908416.jpg

PXL_20230529_194915829.jpg

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

PXL_20230529_200024419.jpg

Nice touch on the grease caps, oring seal

PXL_20230529_200021614.jpg

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

PXL_20230529_205814030.jpg

PXL_20230529_212242972.jpg

Just need to bleed the brakes

PXL_20230529_212441693.jpg

PXL_20230529_212455136.jpg

PXL_20230529_174924219.jpg

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.

 

  • Like 2
Link to comment
Share on other sites

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?

Link to comment
Share on other sites

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).

  • Like 1
Link to comment
Share on other sites

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:
P1090925.JPG

P1090934.JPG

 

Edited by Captain Obvious
  • Like 3
  • Agree 1
Link to comment
Share on other sites

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:
P1090925.JPG

P1090934.JPG

 

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.  

 

Screen Shot 2023-06-17 at 6.19.11 PM.png

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

Screen Shot 2023-06-17 at 6.15.12 PM.png

Edited by HusseinHolland
Link to comment
Share on other sites

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.

 

  • Like 2
Link to comment
Share on other sites

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.

 

  • Agree 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.