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Discussion Starter · #1 ·
I decided my GC needed to be converted to 5 stud, for various reasons...

my existing disc brake rear end was in a fairly sad way, it either needed major overhaul, or complete replacement
The 5 stud conversion offers a greater choice of wheels
And if I end up having to install the H-type gearbox when the FE3-T goes in, i'll be prepared for 28 spline axles.

So....stage 1 was to convert the rear, as it was needing something done, and it looked like it was going to be the most difficult to work out.

I looked at a few possibilities, I was originally trying to avoid changing struts, but that was out of the question as no other Mazdas that I could find use a 30mm strut bracket gap. So I decided on using most GD rear components.

I used GD sedan struts and springs with GC strut tops (not all GC strut tops are a direct fit, dont know why they are different)

Once the struts were changed, everything almost bolts up....the only thing that needed changing was the trailing arm, as the attachment to the knuckle uses a stud rather than a bolt.

So I thought I'd use a GD trailing arm....its the same length but the chassis mount bush uses a smaller diameter bolt. The GE ones are the same as the GD, I ended up using GE ones As I preferred the attachment position of the hand brake cable support.

fitting the trailing arm involved removing the captive nut from the chassis, and drilling the hole out to suit the larger bolt. Its tight, but I managed to get my right angle drill in there to drill the hole out to 12mm. (you could file it if you wanted to )

I then used the GD bolt with the nut left over from the knuckle stud to trailing arm attachment...nice.

End result....the ride height is a bit higher (but I will get lowered springs, these stockies are just temporary to get the car back on the road)

Here is a pic with the rear changed, the wheels are not final, but just temporary until the front is done.



Note the ride height, I was running 14x7 steels all round, probably will end up using the 16x7s off my GD (in the back ground) and fit my FDs to the GD.

Its a shame to have to change the struts, as I was using koni adjustables, but they were 100kkm old.

I was looking at the GE rear (so I could use tokico illuminas or suchlike) but there were more differences, I even looked at BG rear components before deciding that while it was possible I needed a solution a bit quicker.

MOre pics with the wheels off tomorrow.....I have to re do the rear wheel alignment
 
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Discussion Starter · #3 ·
I'll back track on monday and see if I can take some photos of whats there, but it was relatively straight forward.

I also had a look at fitting the suspension from the 2G (93-97) GE model, but I was less sure about the fit....one of the problems is that as far as I know the GE front hubs are 28 spline, where as the GC is 26.

for that reason I wanted to use the GD NA hubs to match my GC driveshafts and gearbox. Later on it makes for an easy upgrade later when I swap in the H-type GD turbo gearbox, I can then just press in the 28 spline hubs.

As for the rear, I looked at the GE rear, the gap between the lateral links, is the same for GC/GD/GE...but the GE looked to be postioned differently relative to the stub axle postion, which might have meant the rear wheel would have been more to the front or rear......I didnt measure it, but it didnt look right to me, I'll see if I can get some photos from the wrecking yard where I buy the parts.

The other thing I was considering was a BG 5 stud rear, but the distance between the lateral links was 30mm less than the GC/GD/GE models, meaning that I would need to fit some spacers to use the GC lateral links. The positioning looked right, but I was running out of time to experiment with spacers....the BG 323 lateral links use bushes with spacers built in....They did not look as though they would fit into either a GC or GD lateral link....dont know about a GE.
 

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Discussion Starter · #4 · (Edited)
Here are some photos of the various parts and explanations.

Here is the back of a GC rear disc hub, note the stud for the trailing arm attachement, and the ruler, showing 125mm spacing between the lateral links



Here is the back of a GD rear disc hub with a "bolted" style of trailing arm attachment...note also the spacing between the lateral links is the same



The trailing arms, text in the image, however the GE and GD trailing arms are interchangeable, (I used GE ones) the hand brake cable attachments are all slightly different.



GC and GD struts (Rear) note the perch on the GD is higher, but overall not much difference in unladen height



Strut tops. text in image



Here is an image of it fitted to the car from the underside



Here is a pic of the left side trying to show the trailing arm attachment, but its mostly obscured by the hand brake cable...text in the image



More pics to come after my visit to the wreckers/junkyard, except I left my mini SD card reader at the office and its the only way I can get photos out of my phone.....pics soon
 

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Discussion Starter · #5 · (Edited)
Here are some more pics of junkyard stuff :

Here is a GE rear hub :



Here is a BG 5 stud rear :



Here is the bush extensions, I was talking about on the BG 5 stud, this allows the narrower hub but without the extensions a GD hub would fit between the lateral links :



Here is a pic of GV wagon spring, just because there was one there, note the really thick wire diameter, its a much more serious spring than the sedan or 5 door.



This is the car that I was referring to as the BG 5 stud, its not really a BG, but rather an Astina sedan v6 1997 (as it is in Aiustralia) I am not sure whether it was sold anywhere else, or what the name was....lantis and 323F might be possibilities

 

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Discussion Starter · #7 ·
The plan is to change over to the GD front.

I had to stop the project to collect some more parts and check the GC drive shafts to make sure that they will fit into the GD F2 26 spline hubs( which I havent yet done).

I had to do the rear as I had a fluid leak in one of the rear calipers, a wheel bearing problem, and damage to the lateral link bush mating surface on the knuckle. Plus i needed to buy two new rear tyres, so It seemed like a good time to do the conversion.

it might take a few more weeks to get to the front. I want to buy some brand new front shocks, rather than use junkyard ones like i did on the rear.

as for heavy braking, I dont notice any difference so far, the rear behaves pretty much like a good condition GC setup. Mind you I havent fully tested it with a panic stop
 

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Thanks for the answer!!

About the GC drive shafts, they don´t fit with your GD 26 spline hubs, a new shaft has to be made using parts of the GC and GD shafts, i´m not sure how to do that, but i know its possible because here in Bogota, i´ve seen a 626 with the front a rear brakes from a 1993-97 626
 

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Discussion Starter · #9 ·
Do you know what makes the drive shafts not fit ?

I was considering what to do if they didnt, I was just going to look at using GD shafts from the F2 non turbo in their entirety.

I guess if that doesnt work I can use the GC in board joints on the GD NA shafts.

I have repaired driveshafts before, so i can pull one apart to try that, but for the time it takes me to do, I'll just drop them into the driveshaft place.
 

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I can see we are agree, but a i was thinking and.... in my case i have a 1987 626 LX i think the shafts, hubs and every thing (brakes and suspension) are the same in your 626, and keep in mind that my car was sold in Colombia, i think the brakes and suspension systems are the same, as i say, but maybe not. I asume that the cars are the same, so the shaf instaled in my 626 has different number of splines so it can´t macth the hub of the disc support of the 1993-1997 626, then, what a mechanic told me is tha you have to take your f2t shaft and cv joint (engine side) and put it together with the 1993-1997 626 (wheel side), thats will fix the problem, he told me (my mechanic) thats not a big deal he says is an easy work. So, i think we are talking the same, my only doubt is that your 626 might be different comparing with my 626.

pd: sorry for my bad english, is hard to explain things in english while i´m still thincking in spanish. i hope you understand what i tray to say.
 

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Discussion Starter · #11 ·
Yes the GE front hubs are 28 spline, which match GE and GD F2T shafts.....which are also 28...so you mechanic is right......

but I am still using my GC gearbox (for now) so what I wanted in this transition stage, is to keep using 26 spline shafts, I cant go to GE front hubs as theyre 28 spline, I'll have to stick with GD non turbo hubs which are 26 spline.

Can I use GC 26 spline shafts with GD non turbo 26 spline hubs.

Or do I use GD non turbo 26 spline shafts with my GC gearbox with 26 spline diff.

Or do I have to make a hybrid shaft using GD non turbo outer joints on a GC shaft with GC inboard joints.

The whole idea is that later on I can easily swap my GD non turbo hubs with either GE or GD turbo hubs when I fit the H5M gearbox which is 28 spline, then drop in some GD turbo shafts.

I believe that all GC models from 83-87 are all the same, all over the world regardless of engine choice, the only options were rear disc brakes instead of drums.
 

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Discussion Starter · #12 ·
OK....I decided to test fit the GC shaft into the GD hub just to clear up the confusion for my own peace of mind...here is what I discovered.

Any more info I will add into the part 2 thread.

Here is a GC right hand shaft :



Close up of the outer joint :



Here is a GD non turbo hub :



and the hub on the shaft :



The only thing I noticed is that the non splined end of the GC hub measures 28mm ID, and the non splined end of the GD hub measures 30mm ID.

So yes the GC shaft has no trouble fitting in the GD hub, and the splines are the same, and the amount of thread protruding from the end of the hub is enough for the nut.

The only problem that I can see is that if the non splined part of the GD outer CV joint is bigger to compensate for the larger hole, I wonder what having an extra 2mm of gap will do by using the GC shaft....probably nothing, but you never know.

from this you can see that it might not be possible to use GD NA shafts in a GC...I posted up a thread in the 1G general to see if some one can measure the GD NA CV joint.

I had a look in the workshop manuals, and there are minor differences in length as measured between the CV joints, but whether than translates into a longer shaft between the back of the hub to the gearbox oil seal remains to be seen.
 

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That step is not used for anything, besides a dust shield for the bearing. It does no load bearing at all. I'll get you some measurements this weekend if I pull the hubs out of the parts car.

Great work BTW. funnily enough, I was thinking about 5 stud conversions to a GC after looking over a nice GC turbo with an FE3 conversion.
 

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OK....I decided to test fit the GC shaft into the GD hub just to clear up the confusion for my own peace of mind...here is what I discovered.

Any more info I will add into the part 2 thread.

Here is a GC right hand shaft :



Close up of the outer joint :



Here is a GD non turbo hub :



and the hub on the shaft :



The only thing I noticed is that the non splined end of the GC hub measures 28mm ID, and the non splined end of the GD hub measures 30mm ID.

So yes the GC shaft has no trouble fitting in the GD hub, and the splines are the same, and the amount of thread protruding from the end of the hub is enough for the nut.

The only problem that I can see is that if the non splined part of the GD outer CV joint is bigger to compensate for the larger hole, I wonder what having an extra 2mm of gap will do by using the GC shaft....probably nothing, but you never know.

from this you can see that it might not be possible to use GD NA shafts in a GC...I posted up a thread in the 1G general to see if some one can measure the GD NA CV joint.

I had a look in the workshop manuals, and there are minor differences in length as measured between the CV joints, but whether than translates into a longer shaft between the back of the hub to the gearbox oil seal remains to be seen.
Those pictures explain exactly what have to be made with the shafts, I hope that next month i will start my 626 brakes proyect, I will post photos of the process.
 

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Quick update to this thread...

As some might have read in the part #2 of this guide (front suspension) I went down a slightly different route and shaved down the GD hubs such that they would fit onto the GC struts.

Tried this method with the rear suspension. I immediately ran into 3 problems.

Problem #1 - hole spacing on the strut is different to the knuckle by about 2-3mm. Not so much of a problem, quick elongation with a carbide tool and it will bolt up.

Problem #2 - the distance between the strut mount and the centre of the stub axle is different between the GD and GC knuckles. This effectively acts as a drop spindle (as the GD is a lot shorter) lowering the car by about 20-25mm.

Problem #3 - directly related to problem 2. The lowering effect looks awesome, but now your tire wont fit as it fouls on the spring perch on the strut. This was the last straw.

I then followed the how-to and installed GD struts with GC tops. There was a comment that only some GC strut tops work with the GD springs. To clear this up ELECTRONIC ADJUSTABLE SUSPENSION STRUT TOPS FIT THE GD SPRING - NON ELECTRONIC STRUT TOPS ARE TOO NARROW. My original strut tops were non electric, not even close. Trip to the wrecker and a quick scout around showed the electric ones fitted perfectly.
 

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Discussion Starter · #16 ·
interesting re the AAS strut tops.

It makes sense now. The car I pulled the strut tops from at the wreckers must have had AAS struts originally despite not having them when I pulled the shocks out.
My original car was a non AAS car, being a four door, AAS was mostly fitted to hatchbacks and coupes.

How did your ride height end up at the rear ? I ended up having to re set my rear springs by about 40mm to achieve what I would call level, i.e. sill panel parallel to the road.
 
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