Rear axle flange gasket

[bpetska]

I am having a hard time finding the gaskets that go between the brake backing plate and the differential housing and the gaskets that go between the axle flange and the backing plate. Is it really neccessary to have gaskets there?
Thanks,
Bill Petska

[jopizz]

Mac's has the one listed for $1.95. Rock Auto has the other one for $0.78.

http://www.macsautoparts.com/ford_thunderbird/ford-thunderbird-rear-wheel-bearing-gasket-1958-60.html

John

[jopizz]

Rock Auto has the other one also. I usually just cut out my own from some gasket paper.

John

[bpetska]

rear axle flange gasket

Thanks John. I was able to get the fel pro 55001 gasket here localy but the hole spacing is not right. I have a call in to Mac's and they are going to measure the hole spacing for me. The original gaskets are .010 thick. The gasket material I can get locally is .030. I wonder if the thickness will make any difference.
Bill

[jopizz]

The thickness doesn't matter. It's not a critical application. The material I use is thicker than what Ford originally used. The original gaskets were like tissue paper.

John

[scumdog]

The thickness doesn't matter. It's not a critical application. The material I use is thicker than what Ford originally used. The original gaskets were like tissue paper.
John

I've even used RTV and no gasket at all.

[simplyconnected]

Tom has a good suggestion regarding RTV. Make sure it is oil-compatible like Permatex Black.

Clean the surfaces with lacquer thinner so they are oil-free, spread the Permatex Black thin, let it 'skin over' for at least 15 minutes, then bolt the flange using Loctite blue. - Dave

[pbf777]

The gasket found between the axle housing flange & brake backing plates, and a gasket between backing plate & axle retaining plate?, serve absolutely no sealing value, as far as gear lube retention. Why Ford installed these originally I do not know. But I believe they were part of a different sealing system not adopted in the final design and were not removed from the engineering (overlooked?) sent to manufacturing. Also, note that any pliable materials between these surfaces may enhance movement, particularly when torque is applied from braking. Scott.

[scumdog]

The gasket found between the axle housing flange & brake backing plates, and a gasket between backing plate & axle retaining plate?, serve absolutely no sealing value, as far as gear lube retention. Why Ford installed these originally I do not know. But I believe they were part of a different sealing system not adopted in the final design and were not removed from the engineering (overlooked?) sent to manufacturing. Also, note that any pliable materials between these surfaces may enhance movement, particularly when torque is applied from braking. Scott.

I take your point but in 30+ years of using RTV for this purpose I've never had an issue and on taking the axles out the housing at a later (lots later in some cases) the backing plate and retaining plate have shown no sign of movement.

And the reason I even use the RTV is so if the axle seal leaks the EP90 will flow down to the outside of the backing plate and doesn't get on my brake shoes etc.

[simplyconnected]

Ford made these axles for many years and they covered many car and truck lines. The rear axle is an 'inverted delta' part as far as 'Quality' is concerned. This is a company internal standard by which all manufacturing must strictly comply. BUT... we didn't have room temperature vulcanizing sealants back then and the first ones degraded with patroeum products.

Today, Ford uses RTV in lieu of gasket material in many applications including oil pans. It has proved to be a trusted sealant, widely used across the automotive industry.

I've never heard of rear flange bolts coming loose. Rear brakes don't do much braking so they produce little torque; certainly not enough to bind leaf springs which would cause wheel hop.

Five or four flange bolts? It seems four do as well as five so Product Development stayed with four but they kept the gaskets. Funny how products come to be. Understand that our engineers at Ford attend the same schools as those from GM and Chrysler. At the same time Chevrolet produced the 409, with a nine degree slanted block deck, Ford came out with the 430 with the exact same nine degree block deck. Neither company had another engine with a slanted block deck before or since. The idea was good but not very practical. - Dave

[pbf777]

gasket or no gasket

Concern for replacing a part removed and not just leaving out "stuff" that a manufacturer engineered in the original assembly is understandable. But , as you disassemble the mechanical item think about it, how does this work, what was the original intention, was it executed properly, can I make it better? Also, particularly with old cars, was someone else here before you and reassembled it improperly or still, had leftover parts on the floor when they were done. All of the listed processes in this thread are common practices which I have witnessed over the years. And none will probably cause the wheels to fly off. But, my thoughts were to suggest good practice and not rely on the over engineering the manufactures provide. Also, sealing the surfaces described will insure that 100% the gear lube, once the axle seal fails, will be routed to the interior of the brake backing plate & drum area (think about it). As far as brake torque applied to this surface. In a "panic-stop", brakes locked situation, the forces that act to overcome the centrifugal rotation of the tire & wheel plus the skidding tire on the pavement with a certain amount of the weight of the vehicle? To many variables to calculate in this thread, but lets just say these forces are significant. Along with the number of fasteners (4 vs 5), changes bolt spacing/patterns, the diameter dimension (3/8" vs 7/16")of the fastener changed with the G.V.W. rating also. Ford exhibited some concern in reviewing the engineering; so we should follow good practice in our assemble processes. Scott.

[simplyconnected]

...Ford exhibited some concern in reviewing the engineering; so we should follow good practice in our assemble processes...

...and we do. This is clearly an attempt to sandwich three sheet metal stampings together. They do not seal anything and they are open to atmosphere and water.

Sheet metal can have waves in it or an 'orange peel' surface. I have seen coils of steel change thickness as the parts are blanked. During a run, the presses rarely change shut height to compensate for part thickness changes, especially in thick parts. Outer skins are different. We keep a very close eye on the draw in particular, with changes throughout the shift.

So, these gaskets are there more for cushion than anything else. Squarebirds use the same brake shoes, front and rear. Since the rear shoes outlast the fronts by two or three times, inverse friction also follows that ratio.

[pbf777]

9 or 10?

Dave, not to hi-jack the topic, just a follow-up, but is the 430 MEL deck at 9° or 10° angle? Scott.

[simplyconnected]

Glad you brought that up, Scott. The 1960 Ford Service Manual says it's 10 degrees in sec 1-41. So, that's what it is. I'll have to readjust my memory banks. - Dave