1988 4runner Gas Tank Restoration Saga (2 Viewers)

[bryan89]

Like most projects with these trucks, you start out with some simple intention, and it ends up snowballing into an entire ordeal that takes way longer and costs way more than you intend. Such is the case with this scenario....

Since I couldn't find anything that compiled all of the required parts / part numbers/ and components to do such a thing, I decided to document this project here on Mud for others as a pseudo-instructional document.

Background:
I have been a member of this forum for a while, but haven't posted anything in the past two years or so because we recently had a baby girl and moved into a new house, so needless to say dad's 4runner project truck /tinker toy got moved into the garage and to the back burner.
However, during that time I was determined to maintain the truck by regularly starting it and moving it around to keep everything in working order, especially since i had just rebuilt the engine, transmission, and rear-end.

So, this snowball story starts with me going out to the garage after cutting the grass to move the truck out of the garage. get in. crank....wont start....crank some more....wont start.....I hear the battery going weak, so i put it on charge. came back later....crank...still wont start..

At this point I am frustrated because it had only been a week or so since i started the truck last. So I break out the FSM and start diagnosing. After a few minutes of testing I find out the fuel pump isn't pumping.
I figured that the pump might be clogged up with bad gas since the truck had been doing more sitting than driving. So i pulled the inspection plate under the rear passenger seat and pulled out the pump and found this.....yummy...

LESSON1: ALWAYS STORE A VEHICLE WITH A FULL TANK OF GAS. OTHERWISE CONDENSATION ABOVE THE FUEL LINE WILL CAUSE RUST. ESPECIALLY WITH ETHANOL GAS THESE DAYS...

so i just created my snowball. and the following posts will document how I rolled it up....

 

[bryan89]

So, I know the project truck is on the back burner, but I convinced the wife that I have to at least maintain this vehicle to the point where I can move it in and out the garage regularly, under its own power.

A quick look in the tank indicated that just replacing the bad pump would only be a temporary solution. I didnt get a picture of it, but the most every square inch of the inside of the tank looked like the fuel pump and bracket.

Additionally, the fuel gauge never worked on the truck since I have owned it, due to a faulty sending unit, (this is a known flaw with these trucks)

So, because of the sending unit, and the internal condition of the tank, I decided to drop it, restore the inside of the tank, replace the sending unit, and replace the pump assembly as well. it was one of those, " while I am in there, I might as well...." decisions.

 

[ferg]

Like most projects with these trucks, you start out with some simple intention, and it ends up snowballing into an entire ordeal that takes way longer and costs way more than you intend.View attachment 1484811

Quoted for truth!

 

[bryan89]

After much research, here is a list of OEM toyota parts that you would need to complete the job.
Note: this applies to 4runners with 22re engine and what I believe is a 15 or 17 gallon tank, but I can't be sure. (maybe someone can confirm)
If you have a turbo 22re, or a 22r with a carb, these parts aren't for you.

Fuel pump bracket: 23206-35160 (bolts into top of tank, positions fuel pump in bottom of tank, has power connections)
Fuel pump bracket gasket: 77169-14010 (seals fuel pump bracket to hole in top of tank)
fuel sending unit: 83320-39695 (mounts in separate hole in tank from fuel pump, this part number included gasket and hardware)
rubber cushion: 23249-43080 (bottom mount for fuel pump onto pump bracket. mine was bubbly alien goo. not rubber anymore)
fuel filter / fuel sock: 23217-35040 (mine was disintegrated over 30 years)
screws (qty 7): 93381-15010 (these mount the fuel pump bracket to the top of the tank)
fuel pump hose: 23239-16010 (small 2" section of hose that connects fuel pump to fuel pump bracket inside of tank)
sending unit gasket: 83361-20030 (gasket was not necessary. included with 83320-39695, but didn't know that at time of purchase)

for fuel pump, I chose not to buy the dealer pump, since it was over $200 and it is just a denso part. (Denso fuel pump part number: 951-0012)

oem parts fische diagram below. (ignore the red box) notice how none of the s#it I needed was pictured.....

 

[bryan89]

Now for cleaning the tank:
I will skip draining the nasty gas and dropping the tank. pretty straight forward operation.
dont forget to disconnect all hoses and electrical connections.

STEP 1: With the tank out, I first took some Dawn dish soap and a good scrub pad to it, just to get all 30 years of road grime off of it.

For treatment, I chose to use a kit from KBS coatings. They boast it will clean, strip, prep, and coat a tank up to 25 gallons. they claim it is environmentally friendly and protects against alcohol blended gasolines (ethanol) amongst a whole mess of other crap that I would never expect to be in a gas tank...go figure. All for the low low price of $68 plus tax, shipping, and handling...
here is a link.
https://www.kbs-coatings.com/Auto-Fuel-Tank-Sealer-Kit.html

 

[bryan89]

STEP 2:
KBS coating says the first step is to use KBS clean, diluted 1:1 with hot water to wash out your tank. and you slosh it around for about 30 mins to an hour.

A couple pointers:
1. Rather than do this all at once, because it would super heavy in the tank, I decided to split this step up into 3 smaller steps, or batches. plus I wanted to see how bad the tank was in increments.

So, FYI, if you choose to do the same, the 2 quarts of KBS clean in the kit is the perfect amount to clean the tank 3 times, if you use one full red solo cup of hot water and one full red solo cup of KBS clean with each cleaning.


2. you need to make sure you seal up all of the holes in the tank, so it doesn't leak solvent crap all over you while you slosh it around. this is a good step to try out our preferred sealing method, because later on in the process, when its acid in the tank, you really dont want it to leak everywhere. I chose to "modify" the old fuel pump mounting bracket since I was replacing it by cutting off all the in tank bracketry portion to make a block off plate, and use some silicone nipples I had hanging around to cover the tube inlets. for the sending unit I did the same, but used a piece of an old paint can lid, because I wanted to save the old sending unit without any additional abuse. that left the filler neck and vent tube, for which i used a glove and hose clamp. that worked well. and the drain plug on the bottom of the tank, I just left the oem plug in there.

**Duct Tape does NOT work for this step. the agent in the KBS clean will eat stright through the duct tape adhesive in 1.5 sloshes. ask me how i know.** Think again.

3. Add some BBs. I also decided to add a handful of good ole' American Daisy BB's as aggregate to help break up the rust. make sure they are steel, not lead.

So for each of the three cleaning cycles, I poured in 1 solo cup of hot water and 1 solo cup of KBS clean.
Then I sloshed it all around for 30 minutes each time, with the BBs in there, before draining it out and flushing it clean with water.

After the first and second time cleaning, I got a bucket full of this nasty crap...so I figured it was working.
the third and final cleaning, it was still orangey-rust colored, but starting to clean up some. so I was happy. I was ready to move on to the next step. Luckily so, because I was conveniently out of KBS clean.

 

[bryan89]

STEP 3:
After the tank had dried in the hot sun for a few hours, I moved onto the next step, which was the acid etching step. For this KBS has a product called Rust Blast, which is part of the kit.

I made sure I had an ample amount of BBs still left in the tank from the previous step, and poured in the entire bottle of Rust blast. DO NOT DILUTE.

Then I shook it around for about an hour or so.

Another pointer:
If you are doing this yourself like I did, the tank gets pretty heavy after a while. So, I used a spare tire to help hold the tank up. Then, taking its roundness to my advantage I rocked the tank back and forth on the tire to get the sloshing action in the tank. Back and forth about 25 times. Then rotate the tank on the tire and repeat. this is much easier than holding it up and sloshing it around at the same time.

 

[bryan89]

At the end of step three, I was pretty happy with what came out of the tank, and how the inside looked. below in the bucket it what poured out after I was done sloshing. and these images are of inside the tank, prior to applying the sealant.

 

[bryan89]

a couple more, after the acid etching step

 

[bryan89]

According to KBS instructions, now the tank has to dry....like really really dry. no moisture what so ever before applying the sealant.
So I used some forced air from the compressor until I couldnt see anymore moisture inside the tank. then I let it sit overnight in front of a fan just to be safe.

I would also like to point out that this is a good time to make sure you get all of your BBs out of your tank. Once you get them all out, look again. Shake it around. hit it with a rubber mallet a few times. trust me there are still some more BBs in there. After I got "all" of my BBs out, I still found 8 more in there when I put the sealer in that I had to fish out while it was wet. and that was a mess that you dont want to deal with...trust me. so spend some extra time here.

 

[bryan89]

STEP 4:
So, the next day I was ready to pour in the sealer. I decided that I also wanted to coat the fuel pump bracket too, since it got pretty roached over the years. So I masked off all of the critical areas including fuel pump ring terminals, and plugged all the openings.
Cant coat the sending unit for obvious reasons.

 

[bryan89]

Next was the tank. I poured in the sealant from the KBS kit and bolted my cover plate back on.
For this step I wanted to make sure it flowed into all the cracks and seam welds. so I made sure my spare tire was in "4Lo" and slowly rocked this baby back and forth for about an hour. drank a few beers...and called it good.

I pulled the cover off and this is what I found...

 

[bryan89]

I was really impressed and happy with it. It looks great.

STEP5: now you have to drain out all the excess KBS coating that didnt adhere itself to the walls of the tank. (which in our case is a lot because this kit is for a tank almost 2X the volume of our tanks)
The reason you have to get the excess out is it is designed to be a thin film. if there is a pool in the corner of the tank, it wont cure properly.

This part was a mess. no way around it. KBS sealer was pouring out of everywhere. dont get it on you or your clothes. it wont come off.

The last part is letting it cure. Even with all the excess poured out, there is still some finite amount that wont come out of the tank. For this, KBS recommends rotating the tank every 5 minutes for the first 30 minutes after you drain the excess sealant. this helps to prevent pooling/puddling.

Now I just have to wait 96 hours for it to fully cure before I can put it back together and put some gas in it.

.......Then maybe I can move the truck out of the garage like I intended to do last weekend.

 

[jgranthevagrant]

Good job. When I did mine, I had to drill and tap all 7 holes on the collar at the top of the tank. It was that or a new tank at $1000 for a real one, or $400 for one without a drain. I also had to replace the little flex hose that leads to the fuel pump. Toyota guys also told me to replace the whole fuel line on the frame rail, but I decided not to do that. It was still available from the dealer.

 

[dirtdobberoffroad]

looks good!

 

[bryan89]

..... I also had to replace the little flex hose that leads to the fuel pump....

hey jgrantthevagrant- do you know the part number for this hose? the one that goes from the fuel pump bracket in above picture to the hard line that runs along the frame rail, right?
it has two flare nut fittings and a fexible hose, about 8 inches long....

I cant find a part number for it, but would like to replace it as well.....

thanks

 

[bryan89]

looks good!

Thanks man. my arms and back are killing me......wish I would have thought of the spare tire trick earlier in the process...but I am happy with it. can't wait for that stuff to cure so I can put my truck back together with all the new shiny parts!.

 

[mattv94]

Excellent writeup.

 

[bryan89]

got around to putting this back together...or at least ready to go back in the truck.
put on the fuel filter on the bottom of pump using provided safety clip. then assembled the pump to the bracket using the cushion at the base of the bracket, section of fuel hose, and 2 band clamps.

In addition to Mr. Toyota's design team, I chose to add a stainless steel band clamp and a piece of fuel hose around the whole assembly for added stability. its rock solid on there now.

 

[bryan89]

then it was time to put everything in the tank and say goodnight for the next 30 years.

I reccomend putting the sending unit in first, mainly so you can still look through the big hole and see if you got the float pointing the right direction. with the bolt pattern for the sending unit being equally spaced 5 bolts on round bolt circle, you could easily screw this up. if the float contacts a wall or the bowl in the tank and doesnt free float, then your gas gauge wont read right. so spend the time to make sure the float has its full range of motion, stop to stop, without hitting any obstruction.

again, this is best achieved without the fuel pump bracket assembly in. this is how it should look: