Rotary Extreme RX7 Build Day 33 Rear Brakes

Day 33

Well I think I should have just named them updates instead of days, however this update was over a period of a week but still totaled about 8 hours worth of work…lol

I forgot to put the shield on the back of the engine where the transmission bolts up so I took care of that. Looks better being all orange vs the black back plate with green shields.

The brakes parts I was waiting on were the springs for the back brake pads and the rear brake caliper rebuild kit. I was missing the rubber plunger on the guide pins and my piston boots were ripped.

When I swapped the rear upper control arms I noticed something different between them, on my 95 the bushing was a solid bushing under load where it bolts to the sub frame. On the spare upper control arms I had the were ones that spin, the same style where the shock bolts to the arm. It made things alto easier to set the pre-load height. Unfortunately I did not find this out until I took the rear strut bar and coil-over out…lol. Once I found this out I put the strut bar and shock back in and swapped both upper control arms with ease. Now I was ready to reassemble the rear suspension and brakes.

The way I reassembled the rear suspension.

1. Its easier to bolt the lower control arm to the trailing arm first before putting it into the sub frame, don’t forget the removable blue thread locker.

2. Place the lower control arm into the sub frame and make sure the solid rubber insulator is facing towards the rear of the car, Install the alignment bolts. (I took a picture where they were before so I could put them back the same way. Easier for re-alignment)

3. Put the axle back into the rear end and support the weight of the hub with a floor jack while you try to line up the bottom bolt through the hub and lower control arm pillow ball. For me the bottom ones were easier.

4. Line up the top hub to the pillow ball in the upper rear control arm.

5. Hook up the toe link.

6. Bolt in the ABS sensor.

7. I raised the suspension about 2 inches ( I measured from the bottom of the top plate on the coilover to the bolt that goes through the top of the hub – 16 1/4 “)

8. Tighten the aligning bolt in the lower control arm the goes in the subframe – this one has a fixed bushing so It should be tightened usually when the car is on the ground – thats why I raised the suspension.

Sooooo – we all make mistake – right? Ummmm due to my nerve damage in my right arm I have lost some strength so I used the 2 wrench trick to tighten it more. The closed end goes over the nut and with the second wrench you put the closed end into the open end of the first wrench giving you a longer handle basically. I used this for the upper and lower bolts going to the hub. The first 3 snugged up fine but they were still able to be turned with some force – red flag 1. The last one did not get as tight as the others so I thought I might be stripping it. I backed it off and then started to re tighten it and then POP !!!!!!!!! The damn bolt broke where the should and threads meet. It took me a few minutes to find the bolt after it shot out the hole. I took a picture to see if you guys can see where the bolt ended up. Kinda like wheres waldo. After I report everything Ill say where it ended up. So – off to the hardware store to find replacement nuts and bolts. Dale Hardware come through again!!!! The original bolts say 10 on the head – I’m guessing its strength is a 10??? Well I found some allen socket cap head bolts rated at 12.9 but the nuts were 10.9. The washers were also 10.9 for the Allen head side and I got some lock washers for the nut side. I got 4 and replaced the other 3 as well because I’m pretty sure I over stressed the bolts. The new ones tightened up nicely with a predictable feel.

Now with the rear suspension done it was time to re-do the back brakes with the new parts. The rear piston boots were ripped so I pulled them out and the grease behind the boot was like paste and rust mixed together. I cleaned it all up and put the new boot in the channel and put the c-ring in to hold it in place. Then with a pair of pliers I pulled the boot open and with my aluminum welding stick I placed the orange grease inside. I used my pinky the smear it around evenly on the inside. This is what it feels like to be a dentist…lol. I pressed down the inner opening until it sat down below the ridge on the piston. I took a picture so you can see the outside and inside lips that hold the piston boot. Lastly I rotated the notch on the piston to line up with the post on the rear brake pad.

I ordered 2 kits to get the 4 springs – same kits but the springs were a little different from kit to kit. I see the rear pads get 1 spring on each side on the top but I put 2 on each side so it would have even spring force between top and bottom. I put the rubber plungers on the guide pins and greased everything up. The pads kept flying apart due to the springs so this is what I did to fix that.

The way I reassembled the rear brakes.

1. Put the rotor on.

2. Put the caliper bracket on.

3. Put the caliper on with just the bottom guide pin – add grease. (the other side I did the piston clean up with the caliper supported by the bottom guide pin)

4. Holding the brake pads install the bottom spring and rotate the caliper up until it holds the pads together.

5. Put the top spring in and continue to rotate the caliper in and verify the piston notch clears the brake pad post.

6. Put the top guide pin in with the plunger – add grease.

7. Reattach the e-brake and clip.

Finally I put the tires back on. The car is still in the air but man o man – does it feel great to see the wheels back on this thing.

So the broken bolt – it flew through the 2 red jacks stand in front of the car and ended up under the transmission.

Until next update – Have a safe shelter in place.