RX7Club.com - Mazda RX7 Forum - 1st Generation Specific (1979-1985)

Watertemp/gauges electrical problems

Badfighterpilot — Tue, 19 May 2026 19:05:08 GMT

Hey. Right now my water temp gauge is not working. I ohmed the sensor and there was a resitance value so that works. I ohmed & check continuity from the sensor to the gauge and its 0hms. My oil pressure works, kind of. At first start it will go to 100 psi (high psi reg) but then drop down to 60 and bounce arround slowly. My fuel gauge and volt gauges are also very slow. And I know my alternator works but it only reads 10 volts running. All this leads me to think the gauge voltage regulator and or an open circuit inside the gauges. What do you guys think, and how would i fix it. Im not very experienced in electrical repair.

Edit: i was also interested in doing a swap with modern motors for the gauges if anyone knows about that.

Steering box seals

Badfighterpilot — Mon, 18 May 2026 02:08:54 GMT

Has anyone been able to find seals that will work on the steering box specifically 81-83

Ttt steering rack thoughts

Badfighterpilot — Sat, 16 May 2026 04:47:31 GMT

I wanted to see what people think about the t3 steering rack. I really would like a rack from mtheory and I know its probably better, but It is also 3x more expensive, and he may not make/have any when I go to swap mine.

Sound insulation material

IdahoHusker — Thu, 14 May 2026 14:36:18 GMT

I�m going to be working on the rear interior of my SE. Now that I have a new seal for the rear hatch window, and I�m sure water won�t leak in like it was before, it�s time to work on the interior materials. I�ve ordered a new carpet kit. The wool like sound material that originally came in the car was disgusting. It crumbled and fibers went flying everywhere. What have you guys found to be a good replacement for it?

I�m also planning on putting down some butyl sound deadening material, like Dynamat or B-quiet material. I�m wondering if I go that route do I need to bother with the wool insulation like material?

Help needed - VERY weird electrical gremlin

antonromano — Wed, 13 May 2026 23:36:50 GMT

Working with a 1980 SA -

First, I have some experience with 12v dc systems. Most recently on a 35' sailboat. Let me tell you, you don't know what fun is until you are wrist deep looking for a bad ground in bilge water from a questionable choice or hanging 40' in the air at the top of the mast to rewire an anchor light which has broken in the conduit 2/3 of the way up...

1980 SA - car starts, runs, drives reasonably well. The ACV was removed when I bought the car and did not come with it. I removed the air pump and the remainder of the anti after burn system since it was doing exactly nothing. I have replaced the alternator. The previous one was on its last legs. This problem was going on before and after the alternator replacement. I do not think it is the alternator itself unless T3 sent me a bad one. I know of a vacuum leak in the exhaust as there is a 3/4 inch hole through the heat exchanger and the thermal unit is questionable. Water pump, thermostat, along with gaskets have been replaced. Oil change and oil pan gasket replaced. As far as I know, everything else stock is still there.

Here is the problem -
When starting the choke does not remain out under any condition.
While idling or driving if I use any accessory - radio, antenna, lights up or down, turn signals, brake lights, head lights!, or even parking lights, heater or A/C fan the engine loses serious power and rpms. To the extent that use of the headlights will actually stall the engine.
Here is where it gets weird -
While idling or driving if I pull the choke out and hold the choke out when turning on any of the aforementioned accessories (or multiple ones) there is no issue and the car runs fine until I want to turn something else on or off. The higher the electrical draw, the more disruptive it is to the engine.

I am semi-retired. I have the time and patience to track every wire and check every circuit. I would love to not do that if possible. If anyone can give me a starting point, it would be greatly appreciated.

Thanks

Sanden SD-575 Compressor Bearings, Seal, and AC System Refresh

Toruki — Tue, 12 May 2026 21:22:35 GMT

*** This is split into posts #1 and #2 due to image quantity limits (12 max per post) ***

I've got the Sanden system, it was R12 and needed a recharge like 10 years ago, at the time I converted to R134 by an indy shop and that also leaked. So I started using R152a based on the excellent information here on the forum. But that also leaked over the course of a year. I've grown tired of recharging it so I've finally looked deeper. Looking with UV dye, I found leaks at the compressor shaft seal and at the connection going into the condenser. I've solvent purged as best I can doing the lines that don't connect to the evap/expansion , the condenser. Basically all the stuff in the bay except the compressor of course. New receiver drier from RA (like $8!). I blew compressed air through the evaporator and expansion valve and saw no oil come through.

This post focuses on the compressor. Here's the leak, clutch face removed at this point.

There's lack of reliable information for the exact SD-575 compressor but here's what I've found. I'm replacing the pully bearing (you could prob just buy a new 5.25" double vee clutch, but I wasn't sure how universal they are. I'll also replace the shaft bearing, the shaft seal, and the cover gasket (squared o-ring). You could try to use a replacement compressor although the models out there seem to be SD508 series and ubiquitous. I didn't want to do that, mostly because I didn't want to get into custom lines/fittings and all of the other questions it raises. So more certainty but also much more time working. I also like that it's the original compressor going back in.

This isn't a step by step tutorial, it's organized by the part you are installing. For a general overview, there are a couple of videos for Sanden compressors sort of like this one but the seal is different. The basics of removing the clutch in video 1 and opening up the front cover in video 2 are directly applicable:

Clutch

Seal

Some Tips and Tricks

The videos give you enough to know what to do and the photos throughout should dispel misgivings about disassembly. Take pictures even when you think you don't need one.

Heat and Cold: I drove out the bearings with various sockets, standard stuff, no torch. For reinstalling, I heated the bore with propane, not glowing red or anything that would compromise the material, change heat treated properties. I also froze the bearings. You need to act quickly reinserting and the freeze helps especially with the initial insertion. But the bearing heats back up quickly with the hot bore to get a good alignment and first whack right away. Use a dead blow hammer and a piece of wood to protect at first, an appropriate socket after that and ***always drive against the outer race when installing bearings***.

The shaft bearing will arrive greased up but it is an internal part, exposed to the Ester oil. You must clean it entirely and relube with Ester. I used brake non-chlorinated cleaner and an ultrasonic cleaner and it barely made a dent. Simple green full strength and a toothbrush was much quicker. *Very light* compressed air after that. Don't spin the 'dry' bearing with the air.

The pulley bearing is sealed and you should just install it.

Install the bolts for the clutch puller enough to fully thread in but don't bottom them out, this avoids damaging the compressor's front cover.

There are a bunch of photos at the end in no particular order, these are good for reference if you have forgotten how something fits. Not comprehensive though!

Tools
- Circlip pliers, good ones. So many circlips! I have a terrible pair and made it work, but the right tool would be a pleasure.

- OEMTOOLS A/C Compressor Clutch Hub Removal / Installation Kit 57150, rent at Autozone for a $105 deposit or buy on Amazon for $25.

- If you're pulling the JH1112 bearing then I found the HF bearing hammer pull did the trick, I happened to already have it.
https://www.harborfreight.com/slide-...ece-62601.html

- If you're using R152a (and you should! it's cheap and easy to charge) then make sure to use Ester oil.

- I did NOT need this to hold the clutch, I just used an impact wrench and the shaft nut came right off, almost too easily.

I also did not need a seal protector.

Here are the exact part numbers I am using. I'd give you links to the parts but they just disappear from eBay. So just google the titles as I've provided them

The Exact Parts That Fit the Sanden SD-575 Compressor

Clutch pulley bearing (mine was singing even though I did my best to repack it)
Koyo 83A694CS30 35mm ID x 55mm OD x 20mm

Shaft main bearing
NSK JH1112 Torrington Heavy Needle Bearing
This felt a bit rough so replacing it.

Gasket kit including the front cover square o-ring and the oil fill/drain plug o-ring
Santech MK2143
On eBay these claim to be compatible with SD505 / SD507 / SD508 / SD510 / SD5H13 compressors. I can confirm that the cover o-ring is the correct part and it measures just under 110mm ID x 1.5mmwide and 1.5mm tall. The old one had compressed to 1.0mm when I removed it. I am only removing the front cover of the compressor (at least for now) as the pistons and performance seemed fine so I cannot confirm that the other gaskets fit this model, they might.

Compressor shaft seal
AC Compressor Shaft Seal Kit Fits SD505/ SD507/ TR70/ TR90/ TR105
The package the new seal parts arrived in was labeled " April 2021 SS0831"
The shaft seal is three parts: the "ceramic carbon" seal, a sold steel plug with an o-ring, and a felt ring to absorb leaks. It's held in by circlip at the front of the shaft but you do need to remove the front cover to take out the seal because otherwise the shaft is in your way. . Below is my old seal and then a photo of the new part from the eBay listing.

Installing the seal for this compressor is completely different than the video indicates. It is a rigid piece that absolutely will not stretch and there is no need to "pre stretch" it to got over the shaft. You do not need "seal protector cover" to insert the shaft into the seal, there is very little resistance because the front of the seal is apparently the important part. The seal is keyed to the rotating shaft an so rotates with it. It is spring loaded and its front surface rotates against the raised section of the steel plug that is stacked just ahead of it. That steel plug has the o-ring which seals inside the shaft-way/nose of the compressor cover. See the photo at the very end that shows the stack order and the front cover.

I chose to install the stack into the front cover with the cover removed. With the shaft removed from the cover, drop the seal in to land on the bearing, there is room as the seal's circumference is smaller than the bore's diameter. Lube it and the plug's o-ring and raised segment with Ester, place it in the bore. I tapped it in lightly with a 14mm deep socket.
Next insert the shaft from the inside taking care to line up the spring cage's flats with the corresponding areas on the shaft (it's the rubber like ring that stays on the shaft).
Rotate the shaft so it seats into the cage flats, do this by rotating and pressing lightly, you might feel it "notch in, you might not, but you should be able to seat the shaft fully onto the face to the thrust bearings/cover.
Hold everything together and set the front cover/shaft assembly with the nose up. The long tube can hang over the edge of your work surface.
Tap the o-ringed plug deeper into the nose bore and install the circlip to hold it all in...you are compressing the seal's spring as you do this.

Mfsw sticks too far out

Badfighterpilot — Tue, 12 May 2026 04:02:15 GMT

My mfsw is sticking really far onto the steering shaft and the steering wheel is hitting it before it seats on the knurls. Im going to check tomorrow to make sure the steering wheel looks is lined up(steering shaft is in the right spot). Am i installing it wrong? The knurl part is flush or a little bit out from the face of the switch.

Steering shaft shear rivet replacement

Badfighterpilot — Mon, 11 May 2026 19:01:26 GMT

So i have 2 steering shafts and both of them are collapsed :(. The rivets that hold them look like plastic. what should I replace them with, would a metal rivet be too strong. I know it dosnt really matter unless you crash the car but I want it to be safe.

GSL-SE seat options

IdahoHusker — Mon, 11 May 2026 17:15:47 GMT

I�m sure this is one of those topics where there are lots of opinions. The seats in my SE are literally toast after having sat in the sun for 13 years. The whole interior is baked and crumbly. The original leather on the seats is missing in large chunks so the exposed foam is disintegrating. Seems all the foam is gone where my butt goes. I had thought about buying replacement skins from lseat.com or racing beat but without the underlying foam I�m not sure that�s a smart idea. I�m going to start looking around for an upholstery shop to see what they recommend.

I�m not opposed to putting some non OEM seats in there if they fit correctly and are comfortable. I found a thread once that had started to list all the seats that �should� fit in a 1st Gen but nobody every really said what seats really worked well.

So, does anyone know of a good replacement seat option and/or in the meantime a simple seat cover that I can put over these seats to help not get crumbly foam all over my clothes?

Low oil pressure with fd regulator

Badfighterpilot — Mon, 11 May 2026 01:57:20 GMT

I've put an fd rear regulator and a spring with shims but my oil pressure is only ranging from 35-70. It also takes a very long time for the gauge to move. Im thinking it might be an electrical issue, any ideas?

fuel tank sender unit.

Glassman10 — Sat, 09 May 2026 14:29:30 GMT

I have a 79 RX7 with sixty K miles on it and have posted here before but it's been a few years with it sitting in the garage ( Heated) It was difficult to start and we established three days back that the fuel pump was working part of the time but was erratic. So, sometimes it would start, run for a while and then die. We replaced the fuel pump and it now works fine. We replaced the filter as well. . So it runs. I am replacing the tires since the old ones are cracked and unreliable and when the rear left wheel ii off, I would like to pull the fuel sender which does move, but not much. I understand it is accessible behind the wheel and we don't see it. Was I wrong in my understanding of the location. I saw one person saying the gas tank had to come out, or at least down and another saying it could be approached with out that PIA. Once I have it out, I read one person saying they simply soaked it in a cleaner and another saying it might just be a bad ground. We can try the ground first but wanted more opinions about it. I do understand the sender is no longer made and was wondering if a sender from a later model might be available and fit? It's overall a very nice machine, garaged for 40 years always heated. If I ever gain any fundamental web/photo skills, I'll try to post a picture of it. Thanks in advance.

Crap GC panhard bar, t3 bar measurements

Holdfast — Sat, 09 May 2026 02:45:09 GMT

So I made the big mistake and bought the ground control panhard bar. It was just about $500 and took 3 months to get it. Right away I was very disappointed with the quality. I've installed the t3 panhard bar on a few cars. Gc bar looks very weak compared to the t3 bar. But GC doesn't expect refunds. So I went ahead with the install. Big big problem bar is way to long. No matter how high or low the axle is. It's not even close. GC tells me they can help me solve the problem all they need is the bar measurements. Give them the bar measurements. Now they ghost me. Haven't heard anything back after several attempts to get ahold of them many emails for over a week. Can anyone with a t3 panhard bar take some measurements of their bar without the adjusters? Total length of just the bar. Then one end to the bend in the middle and the other end to the middle. I realize the gc bar mounts in a different position. I'm just trying to get a idea on what the length should be. Fix it myself. Cost me way too much to throw away. But I'm tempted. So pissed.

Oil cooler leak and pressure sensor consideration

IdahoHusker — Thu, 07 May 2026 16:36:15 GMT

Howdy! A project I need to do on my �84 SE is fixing the oil cooler leak. A quick reminder of my car�s history is that it sat for over 13 years in my friend�s field then I brought it home last year and got it running. I�ve had a blast driving it around.

It now appears to be leaking more and more oil from the lower oil cooler hose. The hose itself is saturated with oil and pretty unsightly. So, I was looking at swapping out both cooler lines with the stainless braided lines from RB. While looking at their website I noticed the oil filter adapter that allows for oil temp and pressure gauge connections. Has anyone used this and is it fairly straightforward to install? My current water temp and oil pressure gauges don�t work. It�s hard to know where they�re faulty as my instrument gauges are spotty, as in my tach sometimes works and sometimes not. The dash lights sometimes are on and sometimes off. When the tach and voltage gauge are working the water temp and oil pressure gauges still don�t work. So, I thought I�d install new ones and mount them somewhere in the car. My current radio setup only uses one DIN so I could put them under the radio as I�ve seen some people do. Not sure where/how I�d put the water temp sensor, still thinking about that.

Anyway, I was just curious as to how difficult of a project this would all be and if anyone had any tips or suggestions?

�84 SE rear window/hatch seal, where to find one?

IdahoHusker — Mon, 04 May 2026 14:30:52 GMT

I�m trying to find a replacement seal for the rear window/hatch on my �84 GSL-SE. anyone know where to find one? I�ve looked at Atkins and Mazdatrix. I see one available in Japan on Ebay. I�m not opposed to buying it there but was hoping to not have to deal with the import duties and all that jazz.

Any suggestions of what other places might have it would be greatly appreciated.

I swapped out the door seals the other day and it made a huge difference in the amount of wind/road noise.

Wiring delete help

Badfighterpilot — Sat, 02 May 2026 19:52:55 GMT

can I delete these wires running toward the carb do I need to keep the one plugged to the carb?