Tire rubs on windshield washer tank - FIX

[billjam]

I have a collection of wheels and tires (and cars!) and decided to try my 930 wheels on a G50 Carrera. I was quite surprised that they all fitted under the standard Carrera wheel arches without interference. However, my joy was short-lived when I got to the left front and checked the tire clearance.

As I am sure many of you have found, wider tires on the front will always hit that stupid windshield washer tank and I am equally sure that someone must have come up with this solution before. Anyhow, I'll post my fix here and hopefully it might help someone.

I estimated that the bottom inside corner of the tank needed to be moved away from the tire by at least 20mm so I elected to cut a 30mm wide wedge out of the tank and weld it back together.
Before welding, I taped the joint closed and trial fitted the tank to make sure I had cut out enough material.



I tried several methods for welding up the seam. I started with a small butane torch with soldering tip, a larger soldering iron and then eventually I got brave enough to use the small flame of the butane torch (about 10mm long) directly on the tank. This worked exceptionally well and I used some strips of scrap from the offcut as filler rod.
If you try this, don't let the area around the joint get too hot - keep the heat close to the joint. And don't forget that this plastic burns, albeit quite slowly and it is easy to blown out!

After a pressure test to check for leaks (none of course ) it was back into the car and now I have a good 10mm clearance to the tire.
For the record, this wheel/tire combination is 7.5" x 17" Cup wheel (ET 23) with 225/45ZR17 tires.

[na2ub]

Nice work. I have never "welded" plastic before. Posts like these remind us all of the possibilities we might not have thought of before. Once you know what is possible, the world becomes limitless.

[johnnywishbone]

used to use a "hot air torch" for welding plastic pipe. that tank is so big, i just left it out. must hold 5 gallons. bold move!

[Wil Ferch]

Some aspects of what you say confuse me.

1.) Why would "wider" tires be a problem?.... seems that hitting the water bottle may be a problem if "taller rolling diameter" tires are used. I guess wider tires *can* be a problem as steered off-center, especially with square-shouldered tires, as the "shoulder" now defines a larger overall diameter with a "stripe" that can hit the bottle. Is that what's happening?

2.) Even at that....notice that the car body itself ( front/lower valance) extends rearwards further beyond the plane defined by the rear-most flat surface of the bottle. Would having the wheels at hard-lock hit the spoiler/valence?

3.) What about the inner wheel arch on the backside? Do you see evidence of tire rubs on the inner wheel-well on the backside-inner portion, again as you hit hard lock? Porsche offered and fitted steering lock-limiting spacers when this occurs.

[jasonlee]

Good solution. I was having the same problem, however, I decided to remove my tank, and replaced with a small stainless bottle in the trunk area. requires filling more often and it is only about 16 OZ, but i find I don't use it that often so its all good.

[Canada Kev]

That's a good solution and solid information for the rest of us. That thing IS rather large - about 8.5 litres I believe.

With my 225s mounted to 17 x 8 wheels, I had no rubbing on the washer tank, just the fender lip, so those got rolled. I might remove my tank at some point in the future. If I install a 3.6 or bigger engine, that space would possibly be used for another oil cooler. I have the additional "intensive" washer bottle mounted in the frunk for that duty anyway.

[NY91184]

Nice job! I like the idea you came up with. When I put larger tires in front the washer bottle wasnt my problem, it was the "vacuum box" that sits sort of above/next to the bottle. Well after the tire rubbed on it for some time, it became dislodged and stuck under the car. After hearing an odd noise for ~30 minutes, I pulled over, to find the underside of my car completely covered in melted plastic. Thats what I call weight reduction

[billjam]

Originally Posted by Wil Ferch

Some aspects of what you say confuse me.

1.) Why would "wider" tires be a problem?.... seems that hitting the water bottle may be a problem if "taller rolling diameter" tires are used. I guess wider tires *can* be a problem as steered off-center, especially with square-shouldered tires, as the "shoulder" now defines a larger overall diameter with a "stripe" that can hit the bottle. Is that what's happening?

2.) Even at that....notice that the car body itself ( front/lower valance) extends rearwards further beyond the plane defined by the rear-most flat surface of the bottle. Would having the wheels at hard-lock hit the spoiler/valence?

3.) What about the inner wheel arch on the backside? Do you see evidence of tire rubs on the inner wheel-well on the backside-inner portion, again as you hit hard lock? Porsche offered and fitted steering lock-limiting spacers when this occurs.

Wil,
Tyres may be larger in daimeter, but not significantly. This isn't a rolling diameter issue, its more related to the squarer shoulders and extra tire width on the outside of the wheel.
In plan view, this gives the front outer shoulder of the tire a bigger swing radius about the steering axis and that just happens to intersect with the tank as you get close to full lock. Everything else is well clear.
Clearance between the inner guard and the inside of the tire also doesn't seem to be a problem because all the extra width is on the outside.

This car isn't lowered (so far!) so problems with fender lip clearance aren't an issue for normal driving, although I haven't really pushed the suspension down to its limits on lock yet. That's another bridge for another day ...

[HarryD]

Just a point to consider, not all plastics can be hot air (heat) welded. Before you embark on this route, find a sample to test if you will suceed.

[suckho]

I just found this thread when searching solution to the same problem.. I fixed (or tried to fix, not sure yet if it is water proof or not) my washer fluid tank today.. I thought that it was broken due to wider tires previous owner used, but then I turned steering wheel all the way to right and noticed that even the current 205/55/16 winter tires hit the tank. Is this normal or is the bottle somehow in wrong orientation or position? My first thought was that I'll try to move it somehow towards to make more room, but not sure if that is possible.. The solution proposed in this thread would surely work, but it is a bit more extreme.

Here is a picture of it before my fixing attempt: