1998 V70 R rear sub-frame cracked... I need help

matt122s · Post by **matt122s** » 13 Oct 2019, 09:32

Hi All,
I need your help and advice. I picked up a 1998 V70 R about a year ago with high mileage, about 325,000. It ran really well and the body was really straight and was only $500.00 so I pulled the tiger and bought it.The drive shaft wasn't installed when I bought it but it was included, the center support was rusted and broken. I thought I would just drive it as a FWD and eventually repair and reinstall the driveshaft and have an AWD. I did the T.B., tensioner, idlers, water pump, seals, plugs, cap, rotor, ignition cables, all filters, everything needed to get it to stage 1. I love the P80 cars. This is my second '98 R, I've had 850 sedans and wagons. About a week ago I found a leak in one of the fuel lines above the fuel tank. I was able to temporarily repair the fuel leak... BUT when I was under the rear end I saw that on both left and right sides where the rear sub-frame bolts to the underside of the car the aluminum is cracked and missing some pieces. It is secure for now but I need to fix this, for peace of mind at least. I'm sure it's been this way for the last 50 to 100,000 miles but it bothers me like I almost don't want the car anymore.
I found a 1999 V70 R on CL that is being parted out and the rear sub-frame is there. Can anyone please tell me if the sub-frame is the same or what I would need to do to make it work. Ideally I would like to swap it as is and use the viscous coupling and driveshaft from the 1999 R as well. I know the driveshaft is different between a 1998 and a 1999, there is a difference in length and possibly the center support. Would I need to swap out the Angle Drive from the '99 R as well or maybe just switch the flange. Can this be done, will it bolt up to the transmission in the '98 R? I think there is a difference in the right hand front axle too.
Any help would be really appreciated, I'm really disheartened at the moment. The thought of swapping the rear sub-frame to me is a big job.
Thanks in advance, I can't tell you all how valuable a site/resource this forum is.
Matt

Post by **theWIFES_S70** » 14 Oct 2019, 15:18

Hey Matt,
Not an R or AWD expert. But I believe both rear subframes are interchangeable.

I'd check out https://www.tascaparts.com/ and see if the rear subframes are interchangeable.

matt122s · Post by **matt122s** » 14 Oct 2019, 16:24

Thanks theWIFES_S70, thats a big help. That's a great way to look up Volvo parts, it's nice of Tasca Volvo to put it out there. I went to a pick and pull on the way home from work and they had a 1999 S70 AWD. The rear Sub Frame looked a lot better than mine, they wanted $55.00 for it if I removed it. Your link to Tasca's confirmed that a V70R and an S70 AWD have the same rear Sub Frame.
Thanks again,
Matt

Post by **scot850** » 14 Oct 2019, 16:40

According to Volvo these subframes don't corrode or crack, as they had never heard of the problem. At least that was what they told me when mine on my 2000 V70R did the same thing. Even photos from 3 P80 AWD cars (including another V70R) apparently was not enough to believe there might be an issue.

I have a write up here on re-building the the rear of the car. Biggest issues are several of the bushes in the subframe are N/A and some are special order (some took 5 months).

Biggest problem is finding a good subframe. If I recall correctly any year of P80 AWD will work. The main differences were the mounting plate and layout of the fuel filter and charcoal filter which mount on top of the rear sub-frame.

Try to get a sub-frame from either a southern used parts supplier or West Coast like vandsautodismantlers in Sacramento area, or even Chapman motors on Vancouver island in Canada (where I got mine). Both cases they typically don't see salt on the roads which is the issue of the rust interaction between the subframe aluminum and the steel bolts that mount them as well as the subframe touching the main under frame of the car.

Even used frames are not cheap as they will take a good dismantler 3-4 hours to remove. I got pretty good at removing them and got it down to 2.5-3 hours but I did a few.

Try reading up on the V70R repair I did and look at the links for the fuel system. Again most of the fuel lines are not available any longer but you might get lucky and be able to patch sections. The 98 and 99/00 have different emissions systems but some parts can be swapped. Remember there are V70 XC's and V/S 70 AWD's put there for parts sources also.

I wish you luck! But being blunt, you may be better looking out for a better car from a dry state, but then the issue is rubber rot of bushes.

Neil.

Post by **theWIFES_S70** » 14 Oct 2019, 17:15

Anytime, Matt! Good luck getting that subframe out!

Oh man, Neil... I remember this fiasco... (This is why anytime my brother points to an AWD that can be had for a steal on Craigslist around here, I scream, "NOOOOOOOOO!")

matt122s · Post by **matt122s** » 14 Oct 2019, 17:39

Hi Neil,
Thanks for the advice, I've been reading up on the ordeal you went thru several years ago on your R. It's a great write up with really good pictures. It took me about 6 hours to partially drop the rear sub frame to get the tank down enough to patch the leaking fuel lines. I'm amazed how quickly you were able to accomplish it in. The pick in pull I went to today had a '99 S70 AWD and wanted $55.00 for the complete rear Sub Frame. But I would have to remove it. They will pick it up and place it on stands for me which would really help out. I know the Sub Frame is the same but I need to find out if the VC will work with my driveshaft and Angle gear. I need to weigh your advice about seeking a Sub Frame from out west or down south with whether the car is worth the time and effort to rebuild. It does have high mileage but runs great and the interior and body are nice.
I've been toying with the idea of removing the AWD Sub Frame and installing a FWD rear Sub Frame. It would be a trade off as far as labor goes, but parts would be cheaper. Has anyone on the site done this before?
Thanks,
Matt

Post by **scot850** » 14 Oct 2019, 23:08

There have been a few people talk about this and there was a thread about it not long ago. Not sure it went very far, but does not mean it can't be done. It does mean a lot of parts have to be swapped including the fuel tank and lines.

I would suggest if the frame looks not too bad on the 99 AWD it may be worth pursuing as that is really cheap. The guys at the parts yard know that it is a pig to pull and costs a lot of time. I pulled a spare as I actually found a non rusted one (probably an out of Province car). I think I paid about $75 CDN for that one, but the one from Vancouver Island was $650 + shipping as they pulled it.

If they raise the car to give you access then that really helps. You have done this before, so as long as the main bolts loosen then you are laughing. Do check the condition of the bushes you can see before pulling it because if several are bad they may not be available/ fixable.

Obviously watch out for the differences with yours.

The VC you have if it is good then it will work with the axle. You may find that the price is just for the bare sub-frame.

The 98/99/00 all can have different angle gear rear flanges and different flanges at the rear on the VC.

I am not 100% sure but I understand you can change the angle gear rear flange, and then you will need the 99 prop-shaft and then the VC from the 99 as well.

The main differences are the shape of the flanges and the diameters of the flanges. Colorado Driveshaft can re-build the prop-shaft including the center support bearing.

Neil.

Post by **abscate** » 20 Jul 2020, 09:38

matt122s wrote: ↑14 Oct 2019, 17:39 Hi Neil,
Thanks for the advice, I've been reading up on the ordeal you went thru several years ago on your R. It's a great write up with really good pictures. It took me about 6 hours to partially drop the rear sub frame to get the tank down enough to patch the leaking fuel lines. I'm amazed how quickly you were able to accomplish it in. The pick in pull I went to today had a '99 S70 AWD and wanted $55.00 for the complete rear Sub Frame. But I would have to remove it. They will pick it up and place it on stands for me which would really help out. I know the Sub Frame is the same but I need to find out if the VC will work with my driveshaft and Angle gear. I need to weigh your advice about seeking a Sub Frame from out west or down south with whether the car is worth the time and effort to rebuild. It does have high mileage but runs great and the interior and body are nice.
I've been toying with the idea of removing the AWD Sub Frame and installing a FWD rear Sub Frame. It would be a trade off as far as labor goes, but parts would be cheaper. Has anyone on the site done this before?
Thanks,
Matt

Matt ..I’ll ping you about that S70 AWD subframe. I bought Tim’s for parts, But might heroically try to restore it.

I also am considering the conversion to FWD rear end since I have a spare rear end lying around

Post by **scot850** » 20 Jul 2020, 13:46

How is the interchange process going? Have you figured out if the mountings are universal for the FWD and AWD rear ends? If you find out that they are then maybe that may help keep more of the AWD's running even if only in FWD as it will remove a lot of the obsolete parts from the equation.

Neil.

Post by **jimmy57** » 20 Jul 2020, 16:10

The driveshaft changes have to do with fixing runout in the driveshaft. The 98s used a pin machined on longer angle gear shaft and VC shafts to act as centering with a flat flange on both units. The change was to flanges with a shoulder and CV joints on the shaft with thr right OD to just fit into the flange for centering. The extended shafts on either end might dent the caps on CV joints but it shouldn't be a problem. Use bolts on either end of driveshaft that are all the same length as the 98 used extra length bolts as balance wieghts. The later shafts are balanced to a better tolerance when manufactured.