Driveshaft Vibrations

NamVetMatt · Post by **NamVetMatt** » 23 Jan 2008, 18:03

My '90 Volvo 740 straight 8-valve has served me fine for more than a year now. But for the last several weeks I get rumbblings and vibrations felt at the rear on take off and into second gear (automatic). Mechanic has showed me that my driveshaft support bushing was going bad a month or so ago. I am assuming that it is finally making itself known every time I drive the car. But I also get a delayed "clunk" when pulling off from a stop as well as when I put in gear to reverse.

I understand there are at least two different sizes of driveshaft support bearings and mounts for the car. I think it's 106mm and 208mm. How can I make sure which is for me without getting out and under it in the cold weather? Volvo Dealer does not have an easy answer. Also, do you suppose it is my U-joint that is bad?

Anyone out there who can stear me in right direction as to how to replace support and, busuhing and bearing on driveshaft as well as u-joint? [/b]

Post by **sseir39** » 23 Jan 2008, 19:15

The support bearing on the 7 series is not the easiest to replace at least compared to the 2 series. The normally aspirated usually has the smaller bearing. Regarding the clunk: it is possisble the U joints need replacment. Not a bad job.

Get on brickboard.com and look at the RWD FAQ for good information on this subject.

Parts: check with fcpgroton.com

Good luck and have fun,

Dick

Post by **jonesg** » 24 Jan 2008, 10:13

I'm in Boston, its cold here too, but I've been working on mine often enough that I bought some coveralls.

If you wait too long the tranny output bushing can be damaged too, I had to replace both U joints and the transmission output flange , bushing and seal.

My center support bearing was OK , a few guys on the lists have the new one pressed on by a machine shop, but some use a pipe and drive it on themselves. Be sure to mark the 2 peice driveshaft if you remove it, they have to retain their dynamic balance.

NamVetMatt · Post by **NamVetMatt** » 24 Jan 2008, 16:05

Thanks guys for the info. And, jonesg you have given me inspiration...I think. It does look like I'll have to get out there and do it myself since I am still not yet clear. But I am too, too intimidated by Volvo Dealer prices to take it to them. And since I do not know exactly which parts my particular car takes, well, it's like the old saying goes: "If you want it done right, do it yourself.

Matt

Post by **jonesg** » 24 Jan 2008, 17:10

Just saw volvo driveshaft support bearings on ebay for $18 new.

http://cgi.ebay.com/ebaymotors/Volvo-74 ... enameZWDVW

NamVetMatt · Post by **NamVetMatt** » 24 Jan 2008, 18:35

Thanks for the great lead, jonesg. I'm jumpingon that right away.

Matt

Post by **jonesg** » 25 Jan 2008, 06:25

Whilst you're under your car, check your transmission mount, its just a slug of black rubber so its cheap and very easy to replace, mine was falling apart.

I'm a chef, not a mechanic and I gotta say the volvo is the easiest car I've ever owned to work on, at least the 740 is.
Last yr I replaced the timing belt, water pump ,brake disks and ball joints.
Had to buy some tools but I'm still a few thousand $ ahead of the dealer mechanics. Seeing as I already had a compressor I bought some air tools, the impact wrench makes quick work of many niggly jobs such as the crank pulley bolt and driveshaft nuts. Its a lot of fun and very satisfying.

anyway, read the drivshaft faq before starting.

http://www.brickboard.com/FAQ/700-900/D ... eplacement

NamVetMatt · Post by **NamVetMatt** » 25 Jan 2008, 07:50

WOW! that link was exactly what I needed. After reading it I feel I am empowered to tackle the project, even in my moderately cold area. There oughta be some kind of internet championship rewards for info gurus like you. I know you've saved me a serious amount of money at the hands of the Volvo Dealer. My 1990 740 has a 168k and ran great, getting 28 miles per prior to this driveshaft problem and I only paid $300 for it. I got it a little over a year ago from the original owner who has all the service records done by Volvo Dealers. You have given it new life, again. Thanks, jonesg. I now feel the your helpfulness is contagious and has caused me to want to spread help to another when I can. Now, I seek a detailed top of the line repair and maintenance service manual for the car. Any suggestions on who publishes the better one?

Matt [/b]

Post by **jonesg** » 26 Jan 2008, 07:54

Here and the Brickboards FAQ is the best source I know,
you can also post to the board and get expert advise (books don't do that).
Guys are always coming up with better ways to do a job.

Here;

http://www.brickboard.com/RWD/index.htm?model=700

The greenbooks are supposed to be good.
I use the online pdf files, its not complete but theres enough info to get seriously confused. I don't know who put them there- but there they are.!
I'm not the techi type, my electircal work is done with a hammer.

Here; 500 pages of 740 tech info. Take aspirin.

https://blarf.homeip.net/greenbook/gallery/bymodel/740

I paid $500 for my 1990 740 2 yrs ago, just a bit of work now and then and they run and run. Got my volvo from a plumber, I asked him when the timing belt was last changed, he said "oh I never change those", it was "all original".
Plumbers!

Post by **sseir39** » 26 Jan 2008, 08:56

Good stuff! Another thing overlooked many times is the angle at which the carrier bearing is located. As rear springs weaken or you have a heavy load you may get vibration at take off. The entire carrier may need to be raised with washers. This has been my experience.

You have more info than you may want but these are nice forgiving toys to play with.

Dick