Hello - I am new to this forum. I have a 01 and a 99 4-runner. I have had problems with both of them regarding my front roters getting overheated and warped. I live in a metro area where traffic is heavy, so it gets stop and go a lot. I am told and it makes sense to me, that the problem is the rear brakes being shoe type do not stay adjusted and this causes the front brakes to get overworked and over heated and warped. I believe that the 03 4-runners have rear discs. I love my 4-runner and plan to keep it for a long time. Does anyone know of a retrofit kit for putting rear wheel discs on a 01 4-Runner?

 

No retrofit other than using parts from a newer model with existing rear disc brakes.

Increased heat in front resulting in warped rotors:

-Weak Master Cylinder - replace
-Leaking rear wheel cylinders - replace
-Rear backing plate shoe rests grooved - sand flat
-Rear ride height metering valve clogged - replace or blow through it using compressed air
-Adjust rear shoe clearance
-Front caliper sticking -rebuild/replace
-Restricted front brake hose - replace

Try getting the rear wheels off the ground and see if they will turn with moderate force applied turning the rear wheels in neutral with brakes applied. If they do, there is a restriction in fluid flow or a pressure leak.

Good luck!