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Bedford cf vibrations bad after 40mph

Post by Slimm991 » Thu Sep 06, 2018 3:17 pm
Joined: Sat Jun 23, 2018 5:10 pm
Posts: 37
Hi all I have recently replaced my rear wheel bearings due to one of them failing and I have also replace the unversal joints but once I get up to 40mph or over the hole van is vibrating very badly to much to be a badly balanced wheel I have jacked it up on stands and removed prop to make sure it wasn’t front there is no vibration at all in any gear but once prop is back on the vibrating is there on the stands as well so definitely at rear rear prop is roating ok but the small section that hose to gearbox seems a little wobble but it’s had new joints could theses vibration be caused by a wobble prop or the diff maybe the rear wheels seem to be going around fairly true with only minor wobble a little advice on what to do next or change would be fantastic thanks as spent a fortune on her and no results as of yet am thinking of replacing the hole drive train gearbox prop and rear axle just to make sure it goes away she drives beautiful in ever gear up to 40 after this the van starts to vibrating

Re: Bedford cf vibrations bad after 40mph

Post by johnnyonions » Subscribing Member » Thu Sep 06, 2018 3:24 pm
Joined: Tue Apr 28, 2015 11:33 am
Posts: 304
what vehicle is it , my CF250 prop joins the diff with 4 bolts , I had the same trouble , the bolt were not tight enough , any play other than front to back is going to vibrate , twist the prop on both sides of the UJs for play . if one UJ had gone replace the other .

John

Re: Bedford cf vibrations bad after 40mph

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Post by Phil Bradshaw » Club admin » Thu Sep 06, 2018 3:36 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3732
If the vibration feels like bad wheel balance then check tyres for casing failure and, or, loss of balance weights.

If there's nothing obvious to see then swap wheels with the spare until you find the guilty one.

Also check wheel nuts tightness AND whether any nuts bottom against the brake drum - ring marking on the drum from the cone edge of nuts is what to look for.

Nuts with worn conical faces should be replaced. Wheels with worn mounting countersinks also should be replaced.

Another possibility is a worn propellor shaft sleeve yoke and bearing bush inside the back of Vauxhall transmissions: vibration increases with road speed and sometimes the transmission will rattle and grind when decelerating.

Sleeve yoke should be smooth and show no signs of scoring indicating bearing bush failure.
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  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: Bedford cf vibrations bad after 40mph

Post by Slimm991 » Sat Sep 08, 2018 12:59 pm
Joined: Sat Jun 23, 2018 5:10 pm
Posts: 37
Ok so I’ve replaced wheels one by one with only one improvement it gets to 55 now before vibrating it isn’t as bad on acceleration but makes a drone sound when I let of the gas but this only happens if I’m above 40 and am letting off the power no rattling coming from the box recently replaced due to 4th gear failed on my old. Box

Re: Bedford cf vibrations bad after 40mph

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Post by Phil Bradshaw » Club admin » Sun Sep 09, 2018 1:30 am
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3732
Sounds like a problem with the propellor shaft front end which could be related to a worn or damaged bearing bush in the back of the transmission: early stage can produce a droning noise before vibration is bad enough to rattle the transmission.

Fresh oil leakage from the transmission rear seal can be an indicator but first remove the propellor shaft to check the easier stuff first.

Check universal joints for binding as well as free play. If a joint is tight then smack the yoke with a wood or plastic mallet until it frees up. Also spin the centre bearing carrier to check for bearing damage (roughness, rumbling, snatching).

Check the sleeve yoke for wear and scoring and any new damage indicating that bush in the replacement gearbox may have been defective when fitted, or may have overheated due to lack of lubrication and lost its white metal bearing surface.

With the transmission in neutral check the free play of the sleeve yoke in the back of the gearbox when the yoke is inserted up to the dirt/rust line where it normally runs.

The ideal is only just enough free play for lubrication: sleeve should barely move radially (sideways and up and down).
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  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

Re: Bedford cf vibrations bad after 40mph

Post by Slimm991 » Sun Sep 09, 2018 10:21 am
Joined: Sat Jun 23, 2018 5:10 pm
Posts: 37
Ok Phil thank you so much for your speedy response. Is the any way of changing theses bearings or do I need new box again if so I you don’t happen to know of one for sale do you also after a prop shaft sleeve yoke type not flat 4 bolt hole type thank you

Re: Bedford cf vibrations bad after 40mph

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Post by Phil Bradshaw » Club admin » Sun Sep 09, 2018 12:29 pm
Joined: Sun Sep 02, 2012 7:15 pm
Posts: 3732
Fix for worn rear bush -

Image

Bronze bush in the photo is for Toyota (camshaft if I remember correctly) reamed out to 34.5mm finished size of the sleeve yoke which actually is a bit small for the original neoprene oil seal but works ok with the earlier leather and felt seal for CA and FC Victor models.

If you can find a transmission specialist locally then they should be able to come up with similar even if they have to farm out the machining work.

(Part 2 of the fix is an adaptor for fitting a more readily available taper lip seal but there's not enough sleeve yokes spare to play with without breaking up some more propellor shafts which would be criminal - sound shafts are hard to come by these days.)
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  • What is real is not the external form but the idea, the essence of things. Constantin Brâncuși

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