Extreme axle restoration - good or bad idea?

[FireFox31]

Is it a good or bad idea to try and restore a front right axle with a very rusty shaft? Is it possible that too much rust could lead to structural compromise and eventual breakage?

I'm planning to remove and restore the rusty axle on Geronimo while doing a transmission fluid flush. I'll use a wire brush to remove its black coating and loose rust, a wire wheel on a drill to remove the moderate rust, then a sand blasting cabinet to strip it to good metal. I'll then apply POR-15 surface prep and POR-15 paint to the entire shaft.

After that, I'll send it to a machine shop to have its carrier bearing replaced on a hydraulic press. I will also replace three of the four slightly cracked boots on both axles. Might as well remove them while I have the transmission drained.

I think the CV joint is in good enough condition to justify this repair because I haven't felt any cyclical bumps from it. Then again, the entire suspension is a wreck so I might not notice. I'll ask the machine shop to look at the CV joint before bothering to press out the bearing.

What do you think? Good idea or bad idea?

[volvolugnut]

I would not be concerned with the rust on this axle shaft. It is solid cross section and likely much stronger than needed.
volvolugnut

[scot850]

I would agree on that they are over engineered. I'm curious where/what you are using for a carrier bearing? Are you using an OE one or have you found an alternate? Abscate once found me a couple in Turkey from a Ford Transit van that had the same specs, but had a light chamber on one side of the outer race. It worked fine and cost $10 including shipping, so I bought 2!

Neil.

[454cid]

Sandblasting should strip all that with no problem, in one step. No need to take it off in layers. Personally, if I were to clean it up, I'd hit it with a wire wheel on an angle grinder. Por15 has always been advertised as going over tight rust, and may not hold to perfectly clean steel as well. My own experience with it is limited, Though.

Edit: Using an angle grinder means thorough eye protection, a properly rated wheel, and still getting some wires thrown. Last time I did it, I did my best to contain the wires with cardboard "booth". I still used a magnet to pickup strays.

[FireFox31]

Thanks for the input. I won't worry about wearing away too much metal. The process of cleaning and painting is really to stop it from getting worse and to make the carrier bearing easier to replace.

I bought the Febi carrier bearings from FCP. I'll be doing three of these axles, two on cars I'll ultimately sell and one on my spare axle (which I won't need since the one I'm keeping is now a manual with a different axle). I'd use Volvo if it were on a high quality car I'd be keeping.

Thanks for reminding me that POR-15 is better on firm rust. I'll probably clean the axle with a wire wheel on a power drill to remove all the loose rust. Skipping the sandblasting, while fun, would save me a lot of time. I've had good results using POR-15 on a muffler heat shield (and will be doing another one of those along side the axle). I will certainly wear eye protection, an N95 mask, ear mufflers, and my tight fitting work gloves.

[WhatAmIDoing]

Those are solid axles. Way overkill for this application. The machine shop will likely sandblast and paint the axle as part of the carrier bearing replacement (if they are good). Replacing the boots and grease is kind of a pita. You could have them do that too if they don't charge too much, especially since they will split the cv joint before pressing.

[FireFox31]

Thanks. When I called the machine shop, they sounded like they didn't want to mess with the axle but would press on the carrier bearing since it's simple. I plan to hand them the shaft disassembled and ready.
Edit 9/4/23: I did not have to disassemble the axles at all for the machine shop to remove the old and press on the new bearings. They seemed to grab the axle with something which dug lightly into its metal in order to hold it. I covered the cut with POR-15.

I've settled on getting a wire cup brush for a drill to break off the old coating and loose rust. Then I'll POR-15 prep and paint it.

I've replaced CV boots on my old Mercedes axles before so I'm not too scared of the job. I bought the GKN boots from FCP but since reviews said the clamps aren't quite right, I might use my Oetiker clamp guide to buy new ones from Belmetric.

Whoever replaced the boot on the spare axle I pulled from a junkyard didn't tighten the clamp perfectly or used one which was too small and grease leaked out. I really hope the CV joint is still good considering that I feel some binding at extreme angles.

[scot850]

The carrier bearing does not require you to disassemble the CV joints. You can remove it using a cold chisel to split it, or use a cutting disc to partially cut through it and then split the last part with a chisel. The dealer removed it for me on 2 axles with a puller they had, and then I refitted a bearing using a piece of round metal fence pole and a top cap the same size as the inner race and knocked it on with a large hammer.

A wire cup on a drill or more extreme a knotted cup on a grinder will clean the surface well. You can get rust converters to stabilize the the remaining rust and then coat with Por-15. Many sing the praises of Por-15, but I am not one of them. It is possibly one of the better products out there, but I don't find it as good as it claims in our winters. Mind you I have never found even powder coating to be that robust either.

Strange about the claims of the GKN boot clamps not being any good. I haven't had any issues with the supplied with them, unless they have become of a poorer quality since I last used them.

Good Luck!

Neil

[erikv11]

My last set of GKN axle boots on my beater 96 wagon, lasted exactly 5 years and 15,000 miles. All four went on May 2018, all four had splits in the accordion joints this spring.

GKN is still the best bet AFAIK, but they are wearing out quickly on time alone.

[FireFox31]

As it turns out, extreme axle restoration may be more difficult and less perfect than it seems:

The carrier bearing I bought (Febi 9181693) has a rounded profile instead of the flat edge on my 1999 and 2000 axles. It fits into the carrier but the only points of contact will be a thin circumference in the middle. FCP said it only fits 1993-1998 and 2008+, not 1999-2007.

I damaged the carrier bearing by beating it with a hammer to force the axle out of the transmission. I drained the transmission fluid to prevent it gushing out when I pulled the axle like the 1999 I took at a junkyard.

The front right axle for the 2000 V70 NA has part numbers P9445904 and T990621 on it. The 1999 V70 NA axle I pulled from a junkyard has numbers P9463753 and T981106 on it. They're quite different shapes with different boots and clamps. I don't think I have the back up option to use the 1999 axle in the 2000.