The MGA With An Attitude
HOW Is It HANGING? - Exhaust System -- EX-106

On 13 July 201, George Goeppner in Illinois, USA wrote:
"How much clearance is there between the exhaust pipe and the rear axle? When I try to install the exhaust pipe, it hits the rear axle and I can't quite get the long bolt thru the intermediate hanger".

The handbrake cable does commonly touch the exhaust pipe with full axle drop, and no problem as the cable will flex easily (as long as it doesn't flex much).

The rebound straps should keep the axle from hitting the pipe. If the axle hits the pipe, either the pipe is formed wrong or the rebound straps are too long or stretch too much (defective). Axle hitting the pipe on full rebound (car air born or in hard turn body roll) is a recipe for broken exhaust hangers.

For a reference, I jacked up my MGA, put it on stands, let the axle drop to pull the rebound straps taught, and took some pictures. With axle at full drop it does not hit the exhaust pipe (and never has).

These rebound straps are Moss Motors 1978 issue, in service since late 1986 with 244,000 miles accrued. Perhaps they made the parts better 30 years ago. I measured both straps to be sure, They are exactly 9-inches long after 25 years in service (and tight as a banjo string under load). I think they are supposed to be more like 8-1/2 inches long when new (but I don't have the exact design dimension).

The exhaust system is Moss Motors 2008 issue Falcon stainless system, a replacement for an identical system installed in 1986. I recon the parts are formed exactly the same, and the pipe is correct shape. At full drop I can stick my hand in between the exhaust pipe and axle housing, almost one inch of space there. The pipe hangers are original style in good condition (as always).

So if your rear axle is touching the exhaust pipe, I suggest you fix it. Start by measuring length of the rebound straps. If the rebound straps are no more than 9 inches long under load, and you have original style exhaust hangers, then the exhaust pipe must be the wrong shape. Position and angle of the last two bends ahead of the muffler are critical, as this controls attitude of the muffler. The front end of the muffler needs to be considerably lower than the rear end. A local muffler shop bending a pipe to fit may make the mistake of fitting the pipe when weight of the car is on the wheels (drive on car hoist), and they may not test the fit with the chassis raised and axle at full drop.

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