Left rear seal Help

I have a problem I was at the mechanic getting brakes looked at luckily they just needed to be adjusted and that was free but they told me that my left rear axle is slowly leaking fluid on to the brakes. They told me that they were going to have to replace the seal and that it would cost around $200.00 for both seals. I talked to one of my relatives and he said you can jack it up take the brakes and drum off and slip it out and it won’t leak any fluid he claims that it’s a pretty easy job, So what do you all think

nope there is a lot more to it then that.
1. drain rear diff and remove cover.
2. remove wheel ,drum and brake shoes
3. remove pinion pin bolt in the rear diff BE VERY CARFULL NOT TO SNAP IT OFF BECAUSE THAT HAPPENS A LOT.
4. rotate pinion pin and slide it part of the way out and lock it into place.
5. push axle in about 1 inch and remove c-clip in the rear diff.
6. slide out rear axle
7. remove seal.

Ummm, it really depends on which rear-end you have.

If it's a full-floating rear, ya...just pull the axle out, then the drums, and there's your seal.

Ummm, it really depends on which rear-end you have.

If it's a full-floating rear, ya...just pull the axle out, then the drums, and there's your seal.

How would I know Its an 88 350. But thanks for the help so far guys