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Discussion Topic:
1939 rear vibration
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Porsche |
05-20-2017 @ 9:46 AM
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Member
Posts: 10
Joined: Jul 2015
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I have a 1939 standard coupe that is in stock condition. There is a vibration or slight bounce coming from the driver side rear wheel. I have tried my spare in this location but the bounce is still there. Any ideas what this could be?
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trjford8 |
05-20-2017 @ 10:32 AM
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Senior
Posts: 4215
Joined: Oct 2009
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Check to make sure the brake drum is tight on the axle. Remove the cotter pin and then torque down the nut to 150 lbs.
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40 Coupe |
05-21-2017 @ 4:17 AM
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Senior
Posts: 1676
Joined: Oct 2009
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Before tightening the nut it may be good to inspect the key between the hub and the axle to make sure it has not sheared. To do this the brake drum and hub have to be removed. This will also allow a full inspection of the brakes on the one wheel.
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len47merc |
05-21-2017 @ 4:37 AM
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Senior
Posts: 1165
Joined: Oct 2013
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At what speed does the vibration appear and does it worsen with more speed? Other suggestions - have an assistant drive behind you and watch the rear wheels through the entire speed range the vibration exists and observe whether you are experiencing wheel hop on that wheel. Check that shock to ensure it is still damping properly and is not worn out, low on fluid and/or leaking. Steve
This message was edited by len47merc on 5-21-17 @ 6:31 AM
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Porsche |
05-21-2017 @ 8:53 AM
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Member
Posts: 10
Joined: Jul 2015
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Thanks for the tips. I did notice that the shock was leaking when I took the wheel off. Could this be the problem? I will check the torque on the hub nut however I have been told that taking the brake drum off is really difficult and even more difficult to get back on. Does anyone have any tips on this?
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len47merc |
05-21-2017 @ 4:22 PM
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Senior
Posts: 1165
Joined: Oct 2013
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Remove the link connection to the shock and see how stiff the arm movement is (assuming you have original Houdailles/lever arm shocks. If not, check the tube shock for resistance). If it is completely free with no resistance then the shock may be the culprit or may not. If the vibration appeared after years of not having the issue, and the vibration was still there after changing the wheel as you say, then a higher probability this may be the cause. If you've recently been doing some work on the rear brakes and had the rear hub off then perhaps as others have said it was mounted off-center, or not properly tightened, or the pin is sheared, or... Assuming you have good quality tires on both the original driver side rear and the spare, and you know them to be relatively round and properly balanced, then I'd ensure the shock was in good working order. While on that, check to ensure the axle nut is tight and if you've time and the tool to do it pop the drum/hub off and re-seat them to eliminate that as an issue as well - BUT - only do one thing at a time and check it for resolve before moving on to the next so that you know what the issue truly is/was/ever shall be - amen. EDIT - again, is the vibration evident throughout all speed ranges or does it only show up at a certain speed and get worse as you exceed that speed? Steve
This message was edited by len47merc on 5-21-17 @ 4:33 PM
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MICHV8 |
05-22-2017 @ 4:58 AM
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Member
Posts: 436
Joined: Jul 2010
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I would not move the car until you remove the hub and inspect the axle and woodruff key for damage. If your axle breaks while driving, your car will suffer severe damage.
This message was edited by MICHV8 on 5-22-17 @ 5:00 AM
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TomO |
05-22-2017 @ 7:13 AM
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Senior
Posts: 7253
Joined: Oct 2009
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To remove the rear drum, you must have a hub puller that fits in the grove of the hub. Pullers that attach to the studs can cause damage to the hub and drum. Here is a link to a reproduction tool that will do the job nicely. http://www.vintageprecision.com/products/hub_pullers/ Contact a local Regional Group of the Early Ford V-8 Club as someone may have the puller and be willing to help you or loan you the hub puller. The contact information for Regional Groups is available from the LINKS tab in the blue banner on the left side of this page of the website. I agree with Michv8 that you should pull the hub and examine the axle shaft, wheel bearing and axle housing, before driving the car. If any of these parts are worn or defective, they can cause an axle to break. If the axle breaks, you could lose the wheel and do serious damage to the fender and other parts. Examine the axle for signs of cracks near the backing plate and around the keyway. Examine the bottom of the axle housing for signs of wear and pitting. This surface acts as the bearing race and wear can cause the axle to flex and break. Examine the wheel bearing for wear and loose rollers.
Tom
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len47merc |
05-22-2017 @ 9:04 AM
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Senior
Posts: 1165
Joined: Oct 2013
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It would still be interesting and informative to know whether the vibration began with some particular (maintenance or change) event, or did it gradually appear over time, or has it always been there. Or whether this a new car to Prosche or one that is just being brought back to glory after a long slumber.
Steve
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Porsche |
05-22-2017 @ 9:26 AM
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Member
Posts: 10
Joined: Jul 2015
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The car is new to me and unfortunately the previous owner is deceased so I can not obtain any history. It would appear that it had been sitting for 5 or 6 years. The vibration is subtle and does not seem to get any worse as the speed increases. It really is not noticeable unless on a smooth road. I have a very annoying chirp like squeak coming from somewhere in the upper rear deck. The vibration from the wheel makes the chirp more annoying. That is problem for another day. I am going to get some new tires as the existing ones are old and cracked. That could be the problem. Will also look at obtaining a hub puller
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