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View Full Version : "New" (to me) high mileage NA - Definitive "to do" list



Blueiii
06-21-2012, 02:04 PM
I thought it might be a good idea to have this all in one thread somewhere. I'm looking at a NA this weekend that's in my budget and has around 170k. Its bone stock and it will see daily and autocross/spirited driving use, which I suspect is a common combination!

For most people with "new to me" higher mileage miatas, what all do you recommend to bring it back to truly "new" or even better status so it (hopefully) stays reliable?

Here's my list so far:
___Waterpump and Timing Belt (unless verified changed in last 50-60k)
___Brake Pads (inspect, replace as needed)
___Upgrade to stainless brake lines (eliminate expansion in lines)
___Replace rotors (if signs of scoring)
___Drain and replace all fluids (oil, differential, brake, powersteering, coolant, transmission)
___Shifter Boots - replace both
___Shifter bushing - replace with metal
___Replace coolant hoses with new
___Replace shocks with your choice of new

I'm hoping we can put together a single thread where newbies, myself included, can start working through the list of things to bring our higher mileage miatas back to their glory days.

(If this has already been done on the site, mods feel free to delete without reprimand!!! :ninja:)

kung fu jesus
06-22-2012, 10:47 AM
Here is what I would suggest:

Engine

Waterpump, timing belt, camshaft pulley bolt, new woodruff key, idler pulleys, tension spring, cam seals, crankshaft seal, accessory belts, valve cover gasket, CAS o-ring, plugs, wires, new coolant hoses (ALL of them), new vacuum hoses.

I prefer the OEM metal waterpump gasket, less chance of it folding or tearing during installation. If you're going to be "in there", you should go with mentality of hitting the reset button on the engine. Unless you have receipts and documentation of what maintenance was performed on the car, it sucks to do half the job, then have to go back in to replace something simple, like the cam/crank seals. What is your peace of mind worth? Autocrossing can stress old parts, like coolant hoses. It would suck to be out having fun at an event and then have a leak develop and ruin the fun. Worse yet, have it destroy something and require a tow. I am surprised how many people forego replacing all the coolant lines when doing a timing belt job. It's so much easier to do with the front of the engine apart (like the heater core hoses). Replace the o ring on the water pipe that runs under the header, coming off the waterpump, too. It's big job, but considering you want it to "like new" condition, you want to cover your bases. Even if if the current water pump is at 50k, replace it. My motto doing this maintenance schedule: "Do it right, do it once." A coolant flush is a no brainer at this time, because you have to open the system anyways. Replace the t-stat, inspect the sensors, change the gaskets. If you have a stock radiator (plastic) and it the tanks look brown, replace it. It is getting ready to crack. Having the radiator out of the car makes the TB/WP job a LOT easier.

Brakes
Pads, lines and rotors only address half the problem. Take the calipers off the brackets and inspect the guide pins. Those pins are the key. The calipers move back and forth on them and they are prone to gumming up with repeated expose to heat, especially from auto-x or HPDE. Neglecting the guides leads to dragging calipers and pads as they tend to bind up if the guides are dirty. Clean the guides, look for pitting and use emory cloth to sand them smooth. Re-lube them using high-temp synthetic lube/grease. Inspect the boots on the guides. Remove them, clean them, grease them. If there is water or dirt, they are probably torn. Replace them. They aren't expensive and most autoparts stores sell them as a kit with new pad hardware. Inspection and lubing of the guides should be done annually if you auto-x or drive the car hard.

Flush the brake fluid. Inspect the brake master for leaks. Check the piston seals on ALL the calipers for cracks or tears. Rebuilding the calipers is pretty easy, if you have too.

Transmission
R/R trans fluid.

You're on the right track by replacing the boots, but I don't suggest the metal shifter bushing. They can cause more damage than help and depending on the year of your car, they can be a bit tricky to remove. I have had a few scary moments trying to remove metal shift bushing stuck in the bottom of the turret on racecars. Instead, I would replace ALL the bushings on the shifter with the OEM plastic ones. Look at planetmiata.net for their shifter rebuild kits.

Inspect the clutch slave. Pull back the boot on it and look for fluid. I suggest just replacing it, it's a common failure part. It's $10. Replace the clutch line with the 949 extended length racing line (braided stainless). This line allows you to remove the curly-cue hard line the slave connects to. A new line removes the aging rubber unit. Removing the curly hardline makes replacing the slave SOOO much easier. It will also give you a bit better efficiency to your clutch hydraulic system. Don't forget to lube the shift fork where the clutch slave terminates. This point is known to dry out and cause some annoying chirping. I suggest changing the clutch master, too. It's $30-50 or less and easy to do.

Inspect the rear seal on the transmission. If is wet, or leaking, replace it. You're going to have to pull the drive shaft. It's rare that it leaks, but check it anyways.

Suspension

Inspect the front steering components. Outer tie rods, lower ball joints, upper ball joint boots. If you see torn or cracked boots on the upper balljoints, replace the boots ASAP. If you see them damaged on the lower balljoints or tie rod ends, replace the balljoints and/or tie rods. Inspect the steering rack bellows for cracks/tears. If you have to replace them, inspect the inner tie rod ends. Put a square on them to check for bent units.

Inspect the swaybar mounting points, front and rear. see if the bushings are torn, dried or loose. Check the mounting points, put a wrench on them. Inspect the frame where the front swaybar attaches. A larger, thicher swaybar can cause the mounts to tear away from the frame if re-enforcments weren't used. Check the endlinks, put a wrench on them too and tighten them.

I suggest replacing the camber bolts on all the control arms. If you do, use the NB units. They have a finer thread and makes it easier for fine tuning alignment settings. They are going to be $8-12 each, you will need 8 of them, so if you want to hold off, it's understandable.

Inspect your springs for rust and breaks. You may want to consider finding new tophats. Yours are probably pretty worn and pretty old.

Drive line
R/R diff fluid.

Inspect the seals. If the diff is moist/wet at the driveshaft or halfshaft points, you have a bad seal (s), replace them. Replacing the halfshaft seals is easy, the front seat at the pinion, not so much.

Inspect the CV boots on the halfshafts (inner and outer), look for cracks, tears, or wetness. If you see this, replace or rebuild the halfshafts.

Check you driveshft u-joints. Excessive slop in the u joints puts a lot of vibration through the differential, leading to R&P frag.


Exhaust

Inspect the exhaust manifold for cracks/ leaks.

Inspect the exhaust system for leaks, missing hangers, warped flanges.

Miscellaneous

Replace the engine mounts. Unless yours were changed in the last 50k, they are DONE. Nothing will improve your shifter feel more than new mounts.

Replace the fuel filter.

Replace the PCV valve.

Clean the throttlebody with throttlebody cleaner, NOT carb cleaner.

Set timing and idle.

Do a compression test. Nothing will tell you the health of your engine better than this. It will also give you a clue to life your car has lived up to this point.

Perform a leakdown test. This will tell you what is aging or potentially damaged internally.

Good luck!

psulja
06-22-2012, 02:06 PM
Great post, KFJ! Lots of good information there to get a car running like new again. Although, all of that at once would get pretty expensive lol.

kung fu jesus
06-22-2012, 02:10 PM
Meh, maybe $500-600 tops in parts, worse case scenario.

A lot of the regular stuff can be done in stages.

psulja
06-23-2012, 12:34 AM
You're on the right track by replacing the boots, but I don't suggest the metal shifter bushing. They can cause more damage than help and depending on the year of your car, they can be a bit tricky to remove. I have had a few scary moments trying to remove metal shift bushing stuck in the bottom of the turret on racecars. Instead, I would replace ALL the bushings on the shifter with the OEM plastic ones. Look at planetmiata.net for their shifter rebuild kits.

Can you elaborate on this? What makes the metal bushings such a pain compared to the OEM bushings? Just asking because I'm planning to rebuild the shifter on my NB in the next couple weeks and am just looking over all my options.

kung fu jesus
06-23-2012, 08:09 AM
On the NA, in my own car, I have had notchier shifting. I have noticed scoring, chunking and notching on the metal bushing. Sometimes it would even make putting the car into reverse extremely difficult. On the NB, on a racecar, I have seen the metal bushing seat into the bottom of the turret from heat and could only remove it with a tap. ***edit: when I say tap, I mean a large tap from a tap and die set. Sort of disturbing when you're wondering if you're going to have to pull the transmission just to get that damn bushing out.***

I understand the premise behind the metal bushing, but I don't believe they are effective. I know a lot of spec Miata guys don't use them for the same reasons.

xjdesertfox
06-26-2012, 07:04 PM
I thought the same thing about the metal bushing, I have a delrin bushing from miataroadster and its awesome!

psulja
06-26-2012, 11:55 PM
Hmm, makes sense. Maybe I'll get a delrin bushing instead. DesertFox, have you driven a car with a metal bushing to compare it to yours? Any noticeable difference if so?

Basically the metal bushing will just make things notchier but more precise? But then can lead to issues later on.

xjdesertfox
06-27-2012, 01:07 AM
I had a metal bushing in my car before the delrin bushing. The metal bushing was an improvement over my broken plastic piece for sure, but I yanked it out when I had to change my turret fluid and noticed the same thing as KFJ, scoring. I had lateral wear marks on it, so I just decided to replace it, the delrin bushing which I used was awesome. You literally have to PERFECTLY fit it into place, as its such a tight fit. The shifting has been great since.

psulja
06-27-2012, 01:10 AM
I had a metal bushing in my car before the delrin bushing. The metal bushing was an improvement over my broken plastic piece for sure, but I yanked it out when I had to change my turret fluid and noticed the same thing as KFJ, scoring. I had lateral wear marks on it, so I just decided to replace it, the delrin bushing which I used was awesome. You literally have to PERFECTLY fit it into place, as its such a tight fit. The shifting has been great since.

Great, thanks for the input!

kung fu jesus
06-27-2012, 08:24 AM
A lot of people think the metal bushing will improve shifter feel. Truth is, there are usually bigger issues at play:



failing clutch hydraulics (slave and/or master)
worn bushings (the OTHER plastic bits on the shifter)
worn wave washers or retaining cups
bad engine mounts
bad differential mounts


The metal shifter bushing may add a more precise feel, but if your transmission is moving around from bad mounts, it can actually make it more difficult to find the selected gear because their isn't any deflection in the bushing. Rebuilding the shifter on the NA transmission is actually pretty easy. Still, misdiagnosis of the symptoms can amplify the problem.

Blueiii
07-04-2012, 07:50 AM
Awesome thread is awesome.

Thanks KFJ. I definitely won't be installing the metal bushing now.

Based on the car I ended up buying, brakes seem to be the first order of business.

kung fu jesus
07-04-2012, 08:04 AM
Good luck!

I know the temptation to move straight into mods is really strong, but these cars often need some TLC. They are tough, overbuilt little things, so they take a lot of abuse before they really need servicing. If you "reset" the maintenance first before adding mods, it just makes everything easier to diagnose if something goes wrong. That's just my opinion and experience.

My apologies for the grammar in the first post. Sometimes the stream of consciousness is moving faster than I can type, so when I re-read the post later it looks atrocious.

Blueiii
07-04-2012, 04:29 PM
Maintenance is my priority! A lot of times, upgrades and maintenance go hand in hand. (Point in case. . . replacing the brakes with better than oem, replacing the worn out shocks with konis or... coilovers (real, not raceland.)

Vash
07-08-2012, 12:20 PM
^ Indeed! and I fully agree with our black belted savior about changing the coolant hoses and all hoses under vacuum/pressure in general. the first overheat of my current engine happened when a small coolant hose in the throttle body gave up and lost coolant in an alarming speed. Unfortunately, my partner was the one driving and did not notice the temperature climbing until it's too late..

I<3flippyheadlights
07-08-2012, 06:40 PM
There is no reason mods and maintenance can't go hand in hand. The best maintenance thing I ever did was the shocks, I'll say it till I die.