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MG MGA - Tonneau cover zips.

When using a tonneau cover in the rain, water seeps through the zip fabric, and drips into the car.
Is this normal, or do I have a faulty cover?
Nigel Munford

Hi Nigel,
I have never had that problem, but having said that, it hasn't seen too much action. Not sure how it would hold up under a long spell of torrential rain.
Graham M V

Mine drips. If I park in the rain I usually leave a towel across the armrest and seats.

Steve Gyles

The zip is the weak part of the waterproofing - my old one leaked the same as yours but my new one has a small "fly" flap which helps - found it on ebay . You can try rubbing wax on the zip fabric to make it more water tight.
Cam Cunningham

Nigel. Some of the newer tonneau covers are made with synthetic zippers rather than the older cloth and brass types. On a tonneau in good condition you can replace the zippers with the more water resistant types, but it is somewhat expensive. Cam's comment about rubbing wax on the material would be a "field expedient" solution. A better one would be one of the various waterproofing products sold for tents and shoes at camping supply stores. Moss used to sell (may still sell) a "cockpit cover" which covered more of the passenger compartment than the tonneau does and could be fitted over the passanger compartment, with the tonneau fitted, to provide additional protection. The use of both the cockpit cover and tonneau cover significantly reduced, but did not eliminate completely, the amount of water allowed into the passenger compartment when it rained.

Depending on the condition of your current tonneau cover, the use of a cockpit cover, the replacement of the zippers in the current tonneau, or the purchase of a newer tonneau having synthetic zippers would represent the least expensive to the most expensive options.

Les Bengtson

Thanks all.
I will try waterproofing products first, as the tonneau has hardly been used, and I cant justify buying a new one at the moment.
Nigel Munford


The tonneau is the only protection I have on the car when it is parked up. I commuted in it for several years and it stood out in the rain for many hours at a time. As I said above, I simply laid a towel under the zip. Never really found any problem; just put the towel on a radiator when I got home. The inside of the car never got wet from the standing. More came inside while I was driving and I also used the towel to keep the worst off my suit trousers.

That's what driving these old cars is all about! If I had wanted to be totally protected I would have bought a closed in Euro box.

Steve Gyles


Sort of over-kill but I find that if I have to leave the car overnight, I put the top (hood) up over the tonneau.
David Werblow

I once got caught in an unexpected heavy downpour driving with no passenger so the tonneau was fitted just over the passenger seat. There was nowhere to shelter so I managed to get down in the car and zip myself in under the tonneau. I found out the hard way that it leaks along the zip.

Malcolm Asquith

Your comment made me chuckle. I could picture a nosey neighbour walking by, and after checking nobody was around, thought he would open the tonneau to have a closer look......Cardiac arrest!
Graham M V

I fitted a new tonneau in 2005 as part of the restoration. Better than the original, but it defintitely leaks a bit with steady rain. Somewhat improved, by the use of wax (I keep a candle in the boot) as mentioned by Les. Also note that the fit of the tonneau needs to be such that water doesn't puddle near/on the zipper.
- Ken
Ken Doris

Years ago I bought a Robbins tonneau that had a piece of material that extended under the zipper and that kept out a good part of the rain. You just had to open the tonneau lightly to prevent the water to spill into the cockpit.

Cheers, David....
David Honness

Years ago I bought a Robbins tonneau that had a piece of material that extended under the zipper and that kept out a good part of the rain. You just had to open the tonneau lightly to prevent the water to spill inti the cockpit.

Cheers, David....
David Honness

I have only ever opened the zip on my tonneau cover on one occasion when I drove it in rain with the passenger side of the cover fitted. My side of the tonneau was tucked behind my seat.

To be honest the cover flapped about so much that it got on my nerves and it didnt seem to keep very more water out of the car than when it wasnt fitted.

So since then,I have only ever used it to cover the car when it is parked.

So if your zip leaks enough to become a nuisance you could always just have the zip removed and a fit a taped seam to seal it up completely.

Colyn Firth

I meant to add that I discovered early on that you shouldnt put the tonneau cover on the car if you still have the side screens fitted.
The side screens fold the cover up on each side next to the doors and divert ALL the rain onto the seats.
The day I discovered this, we had returned to the car after parking it in heavy rain and found both seats soaking wet and 2 inches of water in the footwells.

Fortunately it was a hot day and by the time we got home the footwells had each turned into "Foot Spas" and our feet were warm but quite wet and wrinkly!

Colyn Firth

I have a "Stay Fast" tonneau from Moss. I use it a lot, even in hard rain the zipper does not leak at all. As was mentioned, this cover has lips that cover the zipper.
G T Foster

I once considered the 'ultimate' tonneau for my commuting. The idea was to have a zipless tonneau with a circular hole with rubber seal for the driver, similar to canoeing. Problem was how to scratch my nose or wipe the rain off my glasses! The design never got off my drawing board of wacky ideas.

The point Colyn makes about flapping tonneaus is valid. I have marks along the top of the passenger door paintwork caused by prolonged flapping.

Steve Gyles

I never had a problem with the zip being waterproof, but then it failed completely. I thought the only option was to buy a new tonneau, (expensive) but then my wife suggested I took it to the local shoe mender, who repairs leather coats. He fitted a new zip for 20.00. If yours leaks Nigel, you might try having it replaced. (and before anybody says it - it's not a load of cobblers!!)
D J Hill

I don't know if it would work for an MGA but in the Spridgets many of us blow up a beach ball and put it between the seats so that it holds the tonneau up just enough to make the rain run off outside of the car.
Bill Masquelier

Not necessary. The body tonneau on the MGA is nicely curved for good drainage, so the only issue is if the zipper may leak.
Barney Gaylord

This thread was discussed between 25/08/2012 and 12/09/2012

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