Poppie51

I have a 1988 Toyota 4 Runner that I am restoring. It has been sitting for years so I replaced the brake calipers and pads on front. I'm sure the rear brakes also need replacing due to sitting up so long however I have put a lot of money into it so far and need to wait a week or two to repair the rear brakes. My problem is the vehicle has brakes but the petal goes almost to the floor before stopping the vehicle. It doesn't appear to have air in the lines. My question is, should my brakes perform better than this even though the front brakes are the only ones being used? I once had a jeep cj7 that didn't have any brake parts on the rear, no brake shoes, springs or anything, only the drum. My front brakes still worked good. The jeep was purchased used so I never knew the parts were missing until I replaced the axle months later. I am going to replace all parts necessary on the rear brakes before I start using the 4 runner due to safety issues but just wondering if I have other problems with the front brakes that I'm unaware of. Maybe a vacuum leak? Any help would be appreciated.

Terrys87

iTrader: (1)

Your brakes should do better. With it sitting for so long, I would go thru everything. Booster, Master/Slave cylinders, pads, and calipers. I fill my brake lines with Marvel Mystery Oil and let it sit for a few days and then flush it out with high pressure air. Lots of gunk will come out. Mine were about the same on my truck for sitting so long and it took all of the above to get them working great again.

Mine is an 85 but am guessing the front disc would be similar in price. It was $20 to have the disc turned but for $25 I was able to purchase new disc. Now when if I hit the brakes, it will put me thru the windshield. Overall cost for my complete brake job was about $200-$250 doing it myself. Well worth the trouble.

scope103

The petal is supposed to fall freely.

If the brake pedal does that, well, now you've got a problem. I assume you haven't looked at the rear brakes. If they are way out of adjustment, you will use up a "lot" of pedal travel to push the pistons out far enough to stop moving. Only once the brake pistons reach something solid will you develop any stopping force. When you take your foot off the petal (er, pedal) the springs retract the pistons and you're starting all over.

Incidentally, DON'T drive a vehicle with inoperative rear brakes. Even though the front brakes (in all vehicles) provide 60-65% of the braking, if you have no rear brakes the vehicle will have a tendency to spin 180° when you go into a skid. You don't want that.

Poppie51

Thanks for the reply. I flushed the lines with brake fluid until it came out clear at all wheels but didn't use any cleaner. The marvel mystery sounds like a good idea. I've used it in fuel but never thought about using it in the brake system. How would you clean the master cylinder?

Terrys87

iTrader: (1)

If you look on line, you can find an OEM Aisin Master Cylinder. Brake fluid softens seals up to the point they are just soggy or spongy. For the cost of a new MC, I would suggest just replacing it with a new one. As old as it is, I would bet it is junk. Anytime I have to swap a part out, I disassemle it and try and see why it failed.

Once you get it running, I would not be surprised to see you have clutch problems. My bet is your clutch slave cylinder is going to fail shortly after you start driving it or leaking real bad. Brake fluid is harsh on rubber seals. If you disassemble your Brake Master Cylinder, you will see the seals on the piston in there, the rubber seals are just mushy.

Search on line for Aisin parts. You will spend a fourth of the cost in cleaning materials for the full cost of replacement parts.

Pedal pressure will just get the dirty fluid out. Use some high pressure air with a rubber tipped air gun and watch the rust come flying out. Nasty stuff, and may not get the lines sparkly clean on the inside but it has to help cut down on the crud in the lines and slow the contamination of the new fluid.

Like Scope mentioned, rear brakes dont play a whole lot into stopping power, but if you ever get into hard braking situation, the rear of the truck will pass the front end if rear brakes are not working.