Took the old unit apart just out of curiosity. The two seams separated quite easily with vise grips after an initial cut with side cutters. The metal is quite soft.
Pic of the lower diaphragm. There are four actual holes at the four points of the 'four-pointed star'.
Pic of the upper diaphragm. You can see where the rubber material has worn/been eaten away so that the center cloth reinforcement is exposed.
This is the backside of the upper diaphragm. There is a distinct smell of gasoline here. The gas has eaten away the rubber, exposing the fabric underneath. With a strong light at the backside of the diaphragm, you can see right through the fabric from the front side.
I think it would be pretty difficult to do a good and lasting repair on one of these.
I'd say some 2-300 count cotton sheeting material and some silicone caulk (best to use automotive gasket type for fuel resistance)...cut into disc shapes with a hole in the middle for the one with the shaft.
Clean up the diaphrams amd metal with laquer thinner....work the silicone into the cloth...smear some on the diaphram...put on and smooth down. Use some around where the crimps are...recrimp....VIOLA...rebuilt vac thinga-ma-bobs....or are those thinga-ma-boobs?
EASY for me to say.....
They'd look like crap...but I'd bet they would work OK.
Maybe thin innertube material glued in the same way?
Hate to see you guys waste all that beer money....
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Looks like ALL the vac advances can be replaced by just one unit...just plug the unecessary opening one some????
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Well, recently finished off the first tank of gas, and have a modest improvement from what I've been averaging - about 23.5 mp(US)gal - up to a whopping 25.5 mp(US)gal! Not what I expected/hoped for, but every little bit helps, and its just one tank. Should probably consider that there has been an unseasonable cold spell (for the B.C. South Coastal area) during most of this time, and I imagine that would affect the gas mileage. Has turned (relatively) quite warm now, so may do better the next tank.
Update - turns out that the only reason it drove so well was the unusually cold weather! We recently had just the opposite - an unusual warm spell - we call it the Pineapple Express here on the B.C. Coast - really warm, and really wet.
So, the 'Express revealed yet another problem - while driving around on Christmas Eve doing all my (very late) shopping, I ended up doing a lot of short jaunts and being in way too many traffic snarls. What with all the hot soaks and slow driving, in the end, done with my heater fan and temp on full and driver's side window down, it was like riding a bucking bronco at the Calgary Stampede - absolutely ugly.
The latest culprit - the HIC valve in the air cleaner. Found the valve itself to be okay, but the thermal wax 'driving element' to be toast. No movement/opening of the valve at all even when run under extremely hot tap water. Discovered the likely problem by popping the hood immediately after a 20 minute jaunt around town locally, and the air cleaner right adjacent to the air inlet HAI/snorkel was hot enough to almost burn my hand. The HAI was running wide open all the time! Not too bad a problem in cold, sub-zero weather, but ugly in warm weather.
Have disconnected/plugged the vac line at the HAI diaphragm until I can get a good used HIC valve, and what a difference! Drives like a dream again, for now, at least.
Does anyone know - are the HIC valves and other thermal wax devices prone to be common failures? Or are they more or less reliable, and I just ended up with a bad one? I presume they are mfgd by sealing in a certain amount of the thermal wax material, and seals, of any type, will fail eventually.
Decided I better just slowly go through ALL the emissions stuff, to confirm everything is okay. Just last night discovered that the VTV on the TP system was installed backwards. Even though the VTV tested okay, someone, at some time, had put it in oriented the wrong way. Another reason for the backfiring on deceleration that led me to this great group in the first place.
I discovered my HIC was bad when I noticed someone had unhooked the flap in the snorkel, allowing the entrance of cool air all of the time. Upon reattaching the rod, the flap would not open. This was in the Summer, and the slow warm-up with the flap always open was not as noticeable (particularly with the motor's other issues). It would certainly be apparent under the conditions you describe, though.
The HIC was $68 at the local STL Toy dealer, but other dealers will have it a little cheaper. The parts guy did say that, to his recollection, it did not fail all that regularly, so a salvage yard might work for a part; he also thought that Corollas of the era used the same valve, which might ease the yard search somewhat - I did not check this, though.
Tom M.
T4WD augury?
"Oh, do not ask, 'What is it?' Let us go and make our visit." T.S. Eliot - "The Love Song of J. Alfred Prufrock"
"Now and then we had a hope that, if we lived and were good, God would permit us to be pirates." Mark Twain
Mine was bad...I got a used one from a next generation Tercel or Corolla...the 12 valve type (I think)...has worked just fine for the last 2-3 years or so.
One I found looked just the same...had a different number on it. Cost $2-3.
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
Got a pre-owned HIC valve from my favourite local wreckers today, and did the hot tap water test - seems to work about right, so put it in, but haven't driven it yet. I did notice the last couple of days that there is a wee bit of hesitation at low/part throttle driving with only cool/cold air coming through the air filter, but no more bucking bronc!
Also picked up an '87 Tercel 2-row rad (from an auto). Won't be a simple bolt-in as the rad hose connections are located a bit differently, but shouldn't be too difficult. No place for the fan switch in the bottom rad tank either - will have to think about that one - haven't got to the rad changeout yet. Both top and bottom tanks are "plastic". Any suggestions? They also had a 'new' single-row stock rad still in an '87 4WD, but wanted to go with a 2-row.
I can't believe someone is crying about not being able to get better than 27mpg out of a big box. I pulled 31, but that was straight highway, 35psi in tires, and no substantial load in the car. On good ole summer gas. Now, I am lucky to get 25 mixed, 27 if mostly driving highway.
I got 28 mpg into a headwind...47 mpg with a tailwind with 600-700 lbs in the car and a roof rack on it.
Heated fuel, acetone, advanced ignition.
3ACPower was bragging about 36 mpg all around...before he gave up on T4WDs.
All in SUMMER WEATHER. Usually get around 28 mpg or less in winter.
One person has tested a 15% gain in mpg by setting up a heat stove on the exhaust....had around 150F intake air in summer. With the T4WD...the lack of power might be a problem?????
Give a boy a gun-give a biatch a cell phone-and pretty soon you almost got yourself a police state.
Orwell said: War is peace! Freedom is slavery. Ignorance is strength...
[quote="waynehoc"]Thought I'd jump in on this thread as I've just replaced the vacuum advance in my '87 FWD Wagon, which seems, initially, to have solved TWO problems.
great pictures.
i got my vacuum advance at Shucks for 96.00.
note: replacing vacuum advance does not require removal of any internal parts in the distributor.
though doing it with the distributor on the car as you did; removal of internal parts would make the job much easier.
pulling the distributor off the engine makes the job easy too. remove distributor cap, remove screw holding vac adv in place and work vac advance out.
Love those Tercell 4x4 wagons but they sure suffer from road noise.
Re the used 2-row rad from the wreckers - was no better than my old single row, so bought a brand newie (a 2-row for an '86 4WD auto wagon. Had to adapt (slightly) the bottom rad mounts in my '87 2Wd wagon to fit it in properly, but it sure works great! Had fun experimenting with lots of stuff while trying to remedy my (moderate) overheating problem, but learned a lot in the process.
Re gas mileage, would be difficult to say what part of my gain was due to the new vacuum advance, and what part due to replacing the bad HIC, but I think the HIC rplcmt did more to increase mileage in my case. After running through three tanks of gas now, my overall average is 29.1 mpg (US gal), so there has definitely been a worthwhile improvement. Remember, my wagon is a 2WD with a 3.58/1 diff ratio. I use my wagon every day to and from work, and driving is mainly town and country (live in an urban area 30 miles from a major city).
