I think I may have found a cure for the shitty RX-4 front brakes. I have lots of extra parts so I started mix-matching old school and 81-85 front brake parts and here is the outcome:

The 81-85 backing plate will bolt up to a RX-4 spindle. If so, then the 81-85 caliper should work as well as originally I used a 79 brake calipers on the RX-4. (btw, thanks to Bwaits for his reply to my ? @ 1st gen section).

In addition, I found out that the RX-3's koni strut cartridge will work also. The RX-3s cartridge is slightly shorter (less than 1/8") than a RX-4 but its a tight fit. Now, I just need to find my extra 81-85 calipers and swap it in my RX-3.

To be continued....

 

Hey Wacky, can you help me with telling me where I can find a set of Konis for my rx-3.

 

http://www.classicgarage.com/rx3rx41.html

 

The gsl-se front and rear disk brake works great on my rx3, the only other upgrade I'm gonna do is add a slotted disk. If I find some time I may do a big brake using wilwood caliper, if your not in a hurry wait. My only problem with this is I cant find any larger size over the counter 4x110 disk brake.

 

I forget to mention that the FB backing plate matches the RX-3 as well. easier to just pick up a front caliper from the junkyard than dig in my garage

 

Hello Wacky

Thanks for the info!!

 

another update: back to the drawing board. it turned out that the backing plate I used for test fitting is from a RX-3, not FB. I need to hire someone from homedepot to mark all my parts \

but the good thing, the old school back plate where the caliper bracket is only 1/8 thick. So making one and cutting the center bore for the spindle shouldnt be that hard to do.


To be continued...

 

the mounting holes wont line up but I feel that sloting the holes on a FB backingplate should be fine. here's a pix of old school backing plate and FB strut/spindle.

 

How did you go with this modification?

 

I proved that its best to just upgrade to a 81-85 front suspension/brakes. simpler but works better

 

Ok, so did you just swap in S2/S3 RX7 front struts complete with S2/S3 RX7 brakes ?

Was there a need to change the RX4 control arm and ball joint over to S2/S3 RX7 aswell ?

Have you got any pics of the installed setup?

Thanks.

 

the 81-85 struts will bolt up to a RX-3 and RX-4 lower control arms with no modification at all except you have to re-do the brake lines. The brake line thread pitch changed in 81 to fine thread so you have to change the end fitting to 81+ (will require to chop the original one and double flare it).

in this RX-4 project has a 13-B TII bridge (built by Rene). I fined tuned the 51 IDA with MSD 6A, RESpeed camber plate, 85 front suspension/brakes with tokico blues and stock RX-7 springs. I tried RB, TMC, Tokico, ground control and ST springs but stockers gave it not so boundy ride since its is low.

this is what I wanted but it was too low.


raised

 

Hey Mel, Ho does it run? I also have a series 5 motor sitting in my garage. I'd like to do a street port on it with an Ida. What e shaft and rotors did you go with?

 

pre-86 e-shaft is what I always use, old 4port 13-B or GSL-SE so I dont have to deal with that t-pellet behind the front pulley

 

Man, if I can only get my RX4 to look like that I'll be really happy. Since we are on the topic of RX4 brake upgrades I did buy a FB booster from the junk yard to try it on the RX4. I took your advice and spent $23 for a good used FB booster. It was money well spent, but I just need to do a very simple mod. The RX4 booster bolt pattern is the same as the FB booster bolt pattern. The only difference is that the RX4's bolts are about 1 1/2 inch longer than the FBs. The RX4 also has that spacer on the pedal assembly from the firewall. I really don't want to swap pedal assemblies so I might just extend the bolts somehow on the FB booster. The RX4 brake MC also fits, but I am upgrading to all FB MC as well as the clutch MC/slave for the tranny and just redo the lines.

FB and RX4 booster:



No firewall or clearance issues with the clutch MC:

 

I was planning on swapping my Rx-4's suspension with all GSL-SE parts and then ordering the big brake kit from re-speed to upgrade the brakes to the FC 4 piston setup. I also want to swap the rear end as well. Get a limited slip and rear disk brakes all at the same time. That's gonna be a while down the road though. Maybe next winter's project.

 

I'm planning on doing the GSLSE front swap as well. Just a bit hard to find it in my area. I do have the GSL strut assembly already and all I need is the caliper, bracket, hub, and rotor from a GSLSE. For the rear I got a 79-81 Celica rear with disc and will put an LSD from a Supra.

 

If you want to avoid the fitting issue on the brakelines and are sticking with an orig type old school master cylinder order the ss brake lines from Re-speed but tell them you are using a FB brakes on a SA chassis (the only difference is you will need to let them know if you are using drum or disc) also since re-speed now has an Rx3 test bed/mule he may have the exact sizing you need.

Mel I though that for the Rx4/Rx7 swap to work right you had to have the lower contol arms from a 76-78 Rx4? share any light on this one as I am heading towards doing this with one of mine as well.

 

Thanks Mel. Did you also swap out the RX4 diff got the S3 RX7 diff?

I'm trying to look at what options there are for the RX4 as it seems impossible to get decent shock inserts (adjustable). If I need to go down the track of changing to a different strut then I'd probably prefer to go for a setup with a Ford/GM/Holden 5-stud hub and decent/cheap brake choice and availability.

Or, just keep everything stock and run standard gas shocks with lowerd springs.

Decisions, decisions.

 

Dave,
The flange is the same for SA/FB, RX-3 and RX-4 so its a straight swap.

RX4whore,
If im to do another RX-4 street/track, the only change I would do is to extend the FB strut to match the orig RX-4 tube lenght to get the full negative camber. For street use, this is not an issue. Thats the problem with these old cars, there is no selection (strut cartridge) so swapping to a SA is not really an option.

The RX-4's diffy is different from other old schools so I havent tried anything out. With my prior RX-4s, I had a welded diffy