best sealant for "yellow plastic" washer reservoir crack.

The washer reservoir on my 924 has a small crack at the bottom (conveniently discovered in my garage the day after freshly-filling it with a full gallong of the blue stuff....)

Of course, this is way in the bottom of the oddly-shaped reservoir, so I cannot "plug it from the inside" as there is no way to actually get to the inside part of it (really, a terrible design).  The crack is only about an inch or less long, so I was considering a few things:

1. Just slather the outside with silicone or somekind of epoxy and hope it holds.

2. drill a small pilot hole and try to "inject" a good amount into that area of the tank to seal it from the inside

3. drill a larger hole and try to use a plug (location makes this less viable)

4. some kind of sealing tape on the outside?

IDK....this is the old-school kind of yellowy-white plastic in a 1980s car....what sticks to this stuff? plastic epoxy, something more specilaized?

Remove it, scuff the area with sandpaper, dry it, crazy glue the actual crack and then add a layer of two part epoxy.......or replace it.....

I sealed one by gooping a bunch of 5 minute epoxy on it and letting it cure.

Never had any issues with it after.

Remove, clean, sand to provide a mechanical grip. Apply a quality cyanoacrylate (super) glue. Apply a layer of 6 oz glass cloth and soak that with CA glue. Let cure. Apply another layer of 6 oz cloth at 45* of the 1st layer and soak with CA. That fix should last forever, or at least longer than the car does. 

Go to home derpot, get some Quad caulk.  Smear over crack, never leak again, don’t get any on hootus.  I use it on windows, but have been known to use it on many other things, and it can cure in presence of and displace water.

Or hot melt glue gun after all the previously mentioned prep.....plus widening(a little) the crack for more surface area for the glue.......the last repair on the JD4410 reservoir lasted 10 plus years

Rapidfix.  I have repaired yellowed coolant tanks with it and they would withstand 20psi pressure.

If you don't want to spend $30 for Rapidfix, there's a cheaper way.  Superglue and baking soda.  The two chemically react to form a rock hard substance.  Flow some superglue into the area, then drizzle some baking soda over it until it absorbs all of the liquid glue with some powder left over, then flow in some more superglue, etc.

Knurled. said:

Rapidfix.  I have repaired yellowed coolant tanks with it and they would withstand 20psi pressure.

 

If you don't want to spend $30 for Rapidfix, there's a cheaper way.  Superglue and baking soda.  The two chemically react to form a rock hard substance.  Flow some superglue into the area, then drizzle some baking soda over it until it absorbs all of the liquid glue with some powder left over, then flow in some more superglue, etc.

 

 

Knurled will the superglue/baking soda work on a gas can??

In reply to irish44j :

I repaired one of these in my 88 GMT400, using a tube of loctite brand handyman's adhesive sealant. I chose it because I found a tube of it in my garage, probably bought for a craft project or something. I didn't expect it to work at all, but I was broke at the time, and couldn't afford to replace it (just about every part is still available for this truck).

I took out the reservoir and let it dry for several days after rinsing it out and thoroughly cleaning the crack with my usual go-to solvent, 91% isopropyl alcohol. 

It's been so long, I'm not sure whether I had to repeat the repair initially, but it's held up for about 6 to 8 years. Weather conditions could possibly be a factor. We don't get temperatures below freezing long enough to really matter here, the coldest it's been since then is the high 20s, but it's hot for several months a year (not desert SW hot, FL hot). 

Shoe Goo. if you can get it on the inside and out (maybe using something like a popsicle stick to reach inside?) so much the better. 

Currently that's keeping our cracked Corian kitchen sink watertight. 

Super Glue works pretty well, but I'd recommend hot glue over it (having tried both). I've even used hot glue to replace shards that broke out of mine:

In reply to GameboyRMH :

That's impressive

I ended up using JB "WaterWeld." will let you know how it holds up :)

In reply to Greg Smith :

Shoe Goo is good stuff for a temporary fix.  Fantastic, actually.  But in my experience it only lasts a year or two, then it gets hard and eventually lets loose.

How's about Flexseal? They've got it in an easily dispensable cans.

I've had luck with just hot glue, a lot of adhesives don't stick to that waxy plastic. 

In reply to 759NRNG :

I have no idea.  Try it and see.  I learned about it from something Larry Widmer posted on his site/s forum years back.  Apparently he used it to seal up vacuum leaks on prototyped composite intake manifolds, so maybe.

Oh!  Not only have I used it to fix a broken Porsche 928 coolant tank,  but also a Subaru Legacy radiator.  As well as mundane stuff like a whole lot of interior pieces, and the rim width gauge for our balancer...

I used a $20 plastic tank repair kit fro NAPA, with good results.

Miata Wintercrosser (Deux), washer tank repair

2GRX7 said:

How's about Flexseal? They've got it in an easily dispensable cans.

flexseal tape... done

I hope that JB WaterWeld works out for you.

For future reference, Loctite makes a couple adhesive products specifically for polyethylene. 

There's a 2 part product available at Home Depot. You'll need a patch piece from some kind of donor, but at least you won't have to worry about adhesion. 

If you are getting embritlement from age, ozone etc., you might postpone the inevitable but replacement is on the schedulle.

If it has a hole due to something rubbing against it, the various suggested glues may well work.

In reply to irish44j :

I’ve always used wet patch roof cement for fixing these on the 944/924S series. It’s cheap, readily available, and works wonders ($7 a gallon at Home Depot).  I’ve never had an issue after with the tank after my repairs and have fixed several over the years this way.