Tech Tips: Winter 1994

IN THE BAG

I really enjoy working on my 1973 MGB—and it’s a good thing I do, because it gives me ample opportunity to exercise my limited mechanical skills. The car is, after all, over 20 years old and it is fun to try and get every little thing back into working order.

My latest project was trying to get the windshield washers to work. The ’73 model comes with a plastic bag which hangs on the passenger side fender well, inside the engine compartment. The bag contains a tube which runs to an electric pump mounted just above the bag. The tubing then runs from the pump to the washer jets mounted just in front of the windshield.

My first efforts revealed that the bag had a small cut in it, allowing washer fluid to leak out. I was able to cure this by cleaning the inside of the bag well, and then dabbing a small amount of Silicone sealer on both the inside and the outside of the bag at the site of the cut.

Once I had cured the leak I filled the bag, only to find that the very noisy electrical pump would not draw any water. It has to be primed. So I took a mouthful of tap water (don’t use the blue stuff for this!) and blew it in to the plastic tube that fits down inside the bag. Then I returned the tube and plug back into the filled washer bag. I tried it again and the pump actually pumped the fluid out of the two little jets!

A last item was to adjust the jets so that they actually spray onto the windshield, by use of a fine needle in the hole of the jet.

Clark Shilling

Tulsa, OK

GOURMET GROMMETS

Most grommets used on our cars are made of soft rubber and can be squirmed into place pretty easily. However, every once in a while I come across some really tough ones. For example, the grommets that isolate the wiper motor mounting studs from the base plate in a TR4A, and earlier TRs, and also probably other cars that use the same motor. The nylon grommets that locate the throttle cross-shaft in TR6s, Spitfires, and GT6s are another awkward example.

These grommets are so tough and so oversized that it seems that no amount of lubrication or pressure will get them into place.

The answer is HEAT! Put the grommets in a pan of water and bring the pan to the boil. Let it boil for a good 20 minutes so the grommets will be soft, pliable, and easy to insert. Once they have fully cooled they will get quite stiff again. By the way, be sure you have enough water in the pan so it doesn’t boil dry!

Chris Kantajiev

Palo Alto, CA

WHAT A DRAG

I purchased a 1971 MGB that had not been driven for three years. After several weeks of work it became my daily driver. However, during the process of getting the car running I checked the brake cylinders and hoses for leaks, and the rear drums, rotors, pads, etc., for wear. Everything seemed to be okay.

However, after stopping, the left front brake would hang up and drag for a while. The MG would stop just fine but when I took my foot off the brake pedal the front caliper would not immediately retract. This caused the wheel to drag and wear the brake pads rapidly. I pulled the calipers and had them rebuilt at the local brake shop.

After installing the calipers the problem was lessened but would still occur occasionally. A few months passed and I then noticed a slight leak on the flex hose to the left front brake. Externally the hose appeared to be okay except for being a little moist on the end next to the caliper. To be on the safe side and not wishing to risk brake failure, I ordered a new hose from Moss.

When I removed the old hose I found that the inside wall had delaminated at the wheel end and was plugging the hose like the ball in a check valve. As the pedal was depressed, hydraulic fluid would flow into the wheel cylinder and extend the pistons, but when the pedal was released, the lining closed the opening in the hose, thus preventing hydraulic fluid from flowing easily out of the wheel cylinder. This had been the cause of my dragging all along! The restriction was not so total that it prevented the fluid gradually seeping out of the cylinder and eventually letting the piston retract.

Since replacing the hose I have had no dragging brake problems.

G. Dighton

Baton Rouge, LA