Bruce Roe's ( Guide to the Long Term Maintenace of  Old GM Cars
Edited by Phil Remaker (

Updated 6/26/2005

[Editor: Have you ever noticed how most service manuals stop dead at 100,000 miles?  That is because no manufacturer wants you to keep a car that long.  Bruce Roe, a regular contributor to thecml, frequently shares his wisdom about maintaining his older GM cars which are WELL past the 100,000 mile mark. He has preventive maintence measures learned in the school of hard knocks, and are time and milage tested, even in GM cars that are considered "unreliable." This page is an attempt to collect that wisdom, in no particular order]


Cars are just money pits, so I minimize car costs and invest in my property instead.  Buy a $2000 car that I can repair myself, not much to fail, no labor costs, no collision insurance bills, and parts are sooo much cheaper.  Drive it to 250,000 miles. 

My cars from the 60s had a lot of maintenance, but my late 70s have all kinds of improvements.  Electronic alternator, HEI, valve rotators, hardened valve seats, plus all the stainless plumbing I put in.  The late cars might be built as well, but with 4 times as many parts there is no way to easily/economically maintain them.  And no drive train can outlast an Olds small block and a THM (Turbo Hydramatic) 400 transmission. 

Short and Long Term Preventive Maintenace Schedule (Time tested!)

2500 miles
      change oil/filter, grease, inspect things like engine/trans mounts, leaks

    check and tweak alignment 
    check wheel bearings and brakes

      change transmission oil and filter
      clean air filter
      gap or replace plugs

      change water pump
      inspect/change rear axle oil
      inspect/service HEI
      change alternator front bearing
      inspect starter/brushes

      change alernator brushes and rear bearing
      change timing chain
      change U joints
      consider transmision (400 switch pitch) swap
      change rear suspension rubber bushings
      recore (custom 4 row) radiator
      rebuild front end
      consider rear axle swap
      consider engine swap
4 years
      change all coolant hoses

10 years
      change brake, fuel (EFI high presure), and power steering hoses
      check condition of gas tank
      swap brake cylinders and calipers. 

GM V8 maintenance Rule Number 1: Change the timing chain every 15 years or 100,000 miles, which ever comes first.  120,000 after that for standard, or when 4 degree slack measured for roller chain. The chain and sprocket are replaced as a set. and I would recommend getting a true roller set.  Once the original plastic is replaced, you can go pretty much by the slack; a good set will last a long time. 

Don't forget the distributor; these wear out too.  The upper bearing grease dries up; the lower bearing gets egg shaped; the vac advance gets stuck, and the weight pivots wear out.  Keeping things lubed on a regular basis helps.  The lower bearing can be
replaced if the shaft is not too bad, but a special diameter ream is needed to finish it.  Better yet, get an HEI. 

If your final drive is leaking, get some new seals (the RIGHT ones are hard to get); otherwise leave it alone.  If you can find the correct cover gasket, you could refill it with AMSOIL.

Replace belts when obviously worn.  Carry spares and tools. 

Carry spare low beam, tail and running lights, fuses, HEI module

Old bearings need new grease, whether we are talking antenna, wheel bearing, or upper distributor bearings.  They can last a very long time, but only if the grease is replaced.  I try to buy new bearings instead of new cars, but greasing is better. 

The front wheel bearings on my Eldorado have grease fittings. 

Avoiding repeated repairs

What's wrong is, if it broke and I repair it, it will break again and I will have to repair it again.  I eventually figured this out.  So the following conversions are recommended when a failure occurs
Plastic parts deteriorate with both time and use, so like a time bomb they will stop your car.  I can show you plastic parts that worked fine in the 70s, but by the 90s they curled up or broke.  And if you actually find a replacement (that's been on the shelf 2 decades), it will already be approaching failure.  If there is no metal equivalent metal, THERE IS NO FIX.  In the old cars, this simply doesn't happen.


All transmissions need drain plugs, to facilitate fluid/filter changes.  Unfortunately, a lot of older GM transmissions did not include one, so it is useful to modify the pan to add one.

I've had a 79 Toronado/Eldorado around for over 2 decades.  I found the 79-81  3 speed to be a pretty reliable transmission, once you put in the mandatory shift kit.  This does include adding a drain plug so I can do transmission oil/filter every 10,000 miles or so.  However, I have had 2 differentials fail, a couple of crystalized teeth break off the ring gear and make a mess. 

A low mileage but old trans needs a seal kit to replace all those "hard-as-a-rock rubber seals.  The expensive metal parts should be just fine.  If a clutch pack fails to hold pressure one day, it could burn up and fill the whole trans with poison: that will be a far more expensive and inconvenient repair. 

[Moral: low milage does not always translate to road-ready.  Age destroys parts, too - even if the car is garaged.]

The Well Stocked Garage for a 1970's Era Car

I have a set of tools in the car; a set of car tools in the garage; a set of metal bending/cutting/drilling/welding tools; a set of metric tools, a set of THM400/425 overhaul tools; a set of chassis work tools; a set of puller/install tools; a set of electronic fab and repair tools in the basement.   Another set of electronic tools at work.  A little discipline keeps everything where I can find it. 

I don't have a problem with a generic puller.  But the ones I have were difficult to use in this situation, so I made a custom version (driven by my steering wheel puller) that fits perfectly and is easy to use. 

My method to not lose parts, is throw everything from  a project in a box.  When the project is finished, the box should be empty.  Some of the mechanics who used to work on my cars had no such organization, as examining the results revealed.  No more.  Some projects, esp ongoing like making things, might take 8 boxes, but they are put away and labeled when not active.

I haven't licked the "mess" problem 100%, but every mess I don't make saves me time and grief. 

There are a few things about car repair not discussed much:

1. Keeping track of tools;
2. Not loosing any parts;
3. Not making a big mess to clean up;
4. Not getting hurt. 

Plan the job carefully

Get the right tools for the job

Any tool pays for itself the first time you use it

The straight forward way to get the job done is preferable to an apparently quick but ultimately frustrating method
   Example: don't be afraid to pull the engine out to get the pan off

Rebuilt vs. Used Engines

My luck with used original engines is far better than with rebuilts.  So I will ALWAYS go for less than a rebuild IF that might fix it. Once the pistons come out, you are full out for a rebuild and break in, with their risks.