I have a bunch of intake manifolds that the rubber is rock hard I mean so hard you cant flex them at all, no visible damage its just the rubber is rock hard been waiting to find a way to breathe new life in them for years finally the other day after running across a old one on the bench I decided I would try a few things.

I have seen kart racers take old hard tires and make them soft and sticky by soaking them in diesel fuel then washing in soap and water makes them stick like glue, only negative side affect is the smell whilst treating them, once word got out about this locally you no longer seen used kart old dry hard kart tires for sale "cheap" in the pits, was a farmer that discovered this trick...

When I wash parts with brake cleaner and or carb cleaner I do it in a tub then pour the used dirty cleaner into glass jars keep it for future parts washing use the dirty stuff only use new for the final rinse, things you do when the price of these cleaners has more than doubled in the past few years, before I just let it evaporate and bought more cleaner 12 cans at a time on sale, by adopting NEW work procedures here at the hoser compound I have cut my solvent expenses greatly. .

Anyways I took that old rock hard Pilot intake manifold and put it in a coffee can of this used solvent and let it soak about 24 hrs then it was softer than it was when new, I broke out the brand new manifold I have and confirmed it was way softer.

I then allowed the manifold to set on the bench for a few days and as you might guess it returned to the rock hard state it was in before I soaked it in the brake and carb cleaner mix.

So I got to thinking soak it again in the solvents and get it soft then remove, dry with a towel then submerge in automotive Engine oil for a few days, it appears to have absorbed some of the Engine oil into the rubber and is now as soft as a new manifold but not like most oil soaked rubber you have seen in the past.

Got it setting outside in the sun I want to make sure the heat form the sun will evaporate out all the solvents it absorbed before the oil soaking see what happens.

Next I soak one then when soft install it on a 39mm carb let it dry a few days see if it will retain the fit on a 39mm carb might be a new procedure for installing carbs in the future.

Need to make something like a chunk of aluminum to put in the manifold and simulate the weight of a carb hanging on the treated manifold then bolt it to my Pilot and drive several thousand miles off road see if it falls apart or splits.

What else could I submerge the manifold in other than Engine oil to soften that might be better to condition the rubber, silicone spray, armorall ?

Thoughts?

Are those factory or aftermarket?

Factory I am playing with 3 different manifolds at the moment the one pictured is the manifold off my Pilot, second one is off a ATC250R Engine, third is a stock manifold off a FL350

Does the motor (( Internal Combustion Engine ? )) oil expand the rubber at all Hoser?

hope it works,good idea to try

http://www.eastwood.com/eastwood-rubber ... -6-oz.html
Just saw this yesterday, don't know how good it is but I have had good success with some of their products.

Shubey

Are there any updates on this?

Try Armor All.
I have a '47 Studebaker, when I pulled the glass I lost most of the window rubber.
However, one of the vent window rubbers was sprayed with Armor All and that one survived.
After soaking it in Armor All the rubber became pliant to the point of being like new, and stayed this way (I haven't seen it in a few years, but it was good for ~5 years).
Now there are reproductions available for the Stude so the old rubber is not needed.

Personally I would shy away from the oil trick.
Some rubber will swell when exposed to gas or oil.
For a tire where your going to wear the rubber off in a few races diesel is cost effective.
For the intake boot 'sticky' is not a quality your looking for (are you trying to catch some of that grit getting past your K&N filter Hoser? ;-)
The intake boot will have some resistance to oil but it dose swell.

After a month or so the manifolds all returned to a rock hard condition need to try it again using the armor all as Lee suggested.

What about just using the manifold as a starting point, removing the rubber, weld on a flat piece of aluminum, then weld on an aluminum tube and get a silicone coupler? You can make it any size you want for oversized carbs and what not.

But, it would be nice to know if a product out there can restore hard rubber

i was going to start doing that pretty soon i have a couple of bad ones that i have removed the rubber from so i just have to make a desin that could be welded to it so u can use an pingle mount

How did this work out for installing 39mm carb?

Maybe this is worth a try?
Need a non,or less destructive way to get the wonder juice into the rubber boot compound.
Using a vaccuum might be more effective/less destructive than boiling?

I would be trialling the actuall silastic type goop formulated to work with fuels,solvents,coat it all over,place in one of those vaccuum bags,or any other vaccuum situ etc then experiment
with different vaccuum pressures?
This way it's drawn into the boot via vaccuum,rather than trying to boil it in?
Also could try some of the mold making kits chemicals?

Not sure your ever get them to be soft and supple again but i have used this stuff for years on cracked manifolds.....either dip or water down with a solvent so you can paint it on........works great and has lasted 8 years on my tecate still looks new...

http://www.ebay.com/itm/BLACK-PLASTI-DI ... 53ed7eab57

Hoser have you tried one of those oil additives you know the type you can add to your transmission to soften the rubber seals to supposedly stop them leaking ,over here there's one from FORTRON called stop leak ,maybe buy a bottle and soak one the manifolds in it for a few hours at a time and see how long it takes to start to soften the rubber if at all !

Isn't this what "seal swell" is? Makes rubber gaskets / o-rings swell a bit and is in a lot of "high mileage" and "Engine restorer" type oil additives and/or oils.

Yeh i reckon it would be the same stuff
But in an additive it would be of a higher concentrate and work a bit quicker
You would have to soak it for a couple of ours at a time so as not to over do it
And maybe heat up the additive and manifold slightly to help it penetrate the rubber
Hey its worth a go ( nothing ventured nothing gained)