Discovery process during fluid changes

Catbert

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Greetings everyone! While my 1975 CSi is in really great shape and I did have a PPI performed prior to being delivered from Florida to Signal Hill, CA, I have been discovering things not right or broken that I need to fix. This is in addition to the projects I planned before buying the car. This is all part of the "getting to know my new car" and "sorting out" process. Changing all of the fluids (oils, brakes, coolant) is tops on my list. I'm a car guy and a DIY'er. I enjoying working on my cars and especially my dream car... making it right and upgrading parts and components. Using high quality hardware is just so satisfying.

I discovered that the oil drain plugs on the engine, gearbox, and differential are different sizes that range from M20x1.5 up to M24x1.5. I don't know why the BMW engineers did this, but it certainly helps to know they did. I replace hex tool plugs with hex head plugs anytime I can. My gearbox drain plug had rounded edges. When I finally was able to get it off, the magnet was covered in metal filings. I'll bet this oil hadn't been changed in many years and yes, it was dirty.

With the differential, I was at first perplexed on how to access the fill plug as it was sandwiched next to the muffler. So, I removed the muffler securing hardware. It only moved a bit but not enough to use the hex tool. My SS exhaust is all welded from the manifold to the muffler. Clean, but not friendly if I need to remove it. At first, I tried to move the muffler up to gain access the to the diffy fill plug, but that didn't work. With some trepidation, I pushed down on the muffler and was able to move it enough to access the fill plug without hearing any awful cracking sounds from the exhaust bending at the header connection flange. Well, at least I won't be doing this very often.

Next, it was time to change the brake fluid. The passenger rear bleed nipple loosened without issue. However, the M7x1.0 34mm driver's side rear bleed nipple was stripped. Yeah, so when was the brake fluid last changed? Using the penetrating oil and heat technique allowed me to remove it using vice grips. All of the other nipple screws loosened OK. Still, I will be replacing all with SS bleed screws. Hopefully, when I'm ready to change the coolant I won't discover any issues. As the Zen Master says, "We'll see."
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This is also where realoem is your friend, you can look at all of the parts you’re going to be accessing so can already order what is needed. Typical sources are in the FAQ - autohausAZ, FCP euro, ECS tuning and RM European have all received a lot of my dollars. Worth trying to do a little bundling since many have free shipping above $49 or $99
 
This is also where realoem is your friend, you can look at all of the parts you’re going to be accessing so can already order what is needed. Typical sources are in the FAQ - autohausAZ, FCP euro, ECS tuning and RM European have all received a lot of my dollars. Worth trying to do a little bundling since many have free shipping above $49 or $99
Hello e9Leveque! I first try to find my parts on Amazon. Then, I just go into general search and see what pops up. AutohausAZ, FCP euro, ECS tuning and others are sites I commonly come across. When I get stuck, I message SFDon and TomHom. The only problem sourcing parts overseas is having to wait.
 
Hello e9Leveque! I first try to find my parts on Amazon. Then, I just go into general search and see what pops up. AutohausAZ, FCP euro, ECS tuning and others are sites I commonly come across. When I get stuck, I message SFDon and TomHom. The only problem sourcing parts overseas is having to wait.
and when you aren't buying from an individual, there's that wonderful surprise called the djt tariff and the UPS surcharges
 
I have ordered some items from Amazon but quality is a bit spotty unless you’re sure you’re getting an OEM part. Don’t get me wrong, I give Amazon thousands of dollars a year for other things, for this I’ve found the other sources a bit more reliable. Also may be worth ordering a bunch of 8.8 bolts from Belmetric in the standard sizes - M6 and M8. Another scenario where I started off ordering a nice pack of bolts from Amazon and the threading was correct but some needed a 10mm socket for the top, others an 11, others a 12. Makes any future work pretty obnoxious. I pulled those off and replaced with correct ones from Belmetric. Likewise with nuts. An M6 nut means it accepts an M6 bolt but there’s variability in the size of the actual nut’s outer diameter which affects what socket is used to remove it. Same with Harbor Freight - I have loads of tools from them and think for the price can’t be beat, but their fastener packs are less perfect for our vehicles.
 
I have ordered some items from Amazon but quality is a bit spotty unless you’re sure you’re getting an OEM part. Don’t get me wrong, I give Amazon thousands of dollars a year for other things, for this I’ve found the other sources a bit more reliable. Also may be worth ordering a bunch of 8.8 bolts from Belmetric in the standard sizes - M6 and M8. Another scenario where I started off ordering a nice pack of bolts from Amazon and the threading was correct but some needed a 10mm socket for the top, others an 11, others a 12. Makes any future work pretty obnoxious. I pulled those off and replaced with correct ones from Belmetric. Likewise with nuts. An M6 nut means it accepts an M6 bolt but there’s variability in the size of the actual nut’s outer diameter which affects what socket is used to remove it. Same with Harbor Freight - I have loads of tools from them and think for the price can’t be beat, but their fastener packs are less perfect for our vehicles.
Jeff Bezos is too close to being a trillionaire... Musk, too. While I'd rather not contribute to Jeff's proximity to having that much money, I rely on getting what I need from Amazon too much to go elsewhere. So, I buy and buy. I do copious research before buying any parts for my cars. My motto is... "when in doubt, don't buy it!" I will gladly (well, almost gladly) pay a lot more for getting guarateed quality. More and more I use the AI wizard to help decide upon parts quality. Even then, I don't trust anything other than my own research and judgment. Peace!
 
Greetings everyone! While my 1975 CSi is in really great shape and I did have a PPI performed prior to being delivered from Florida to Signal Hill, CA, I have been discovering things not right or broken that I need to fix. This is in addition to the projects I planned before buying the car. This is all part of the "getting to know my new car" and "sorting out" process. Changing all of the fluids (oils, brakes, coolant) is tops on my list. I'm a car guy and a DIY'er. I enjoying working on my cars and especially my dream car... making it right and upgrading parts and components. Using high quality hardware is just so satisfying.

I discovered that the oil drain plugs on the engine, gearbox, and differential are different sizes that range from M20x1.5 up to M24x1.5. I don't know why the BMW engineers did this, but it certainly helps to know they did. I replace hex tool plugs with hex head plugs anytime I can. My gearbox drain plug had rounded edges. When I finally was able to get it off, the magnet was covered in metal filings. I'll bet this oil hadn't been changed in many years and yes, it was dirty.

With the differential, I was at first perplexed on how to access the fill plug as it was sandwiched next to the muffler. So, I removed the muffler securing hardware. It only moved a bit but not enough to use the hex tool. My SS exhaust is all welded from the manifold to the muffler. Clean, but not friendly if I need to remove it. At first, I tried to move the muffler up to gain access the to the diffy fill plug, but that didn't work. With some trepidation, I pushed down on the muffler and was able to move it enough to access the fill plug without hearing any awful cracking sounds from the exhaust bending at the header connection flange. Well, at least I won't be doing this very often.

Next, it was time to change the brake fluid. The passenger rear bleed nipple loosened without issue. However, the M7x1.0 34mm driver's side rear bleed nipple was stripped. Yeah, so when was the brake fluid last changed? Using the penetrating oil and heat technique allowed me to remove it using vice grips. All of the other nipple screws loosened OK. Still, I will be replacing all with SS bleed screws. Hopefully, when I'm ready to change the coolant I won't discover any issues. As the Zen Master says, "We'll see."
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I have never needed to move or remove the muffler to access the fill plug on the diff. Hex socket on a breaker bar or 1/2” ratchet.
 
I have never needed to move or remove the muffler to access the fill plug on the diff. Hex socket on a breaker bar or 1/2” ratchet.
Hi Chris! I looked at numerous photos of other E9s expecting to see a different muffler layout. All that I saw were similar. Now, I have a 5 speed and perhaps a different diffy that may locate the fill plug to where it's not blocked as mine is. Either way, I'm happy that all I need to do is remove a few bolts and pull the muffler down to access the plug.
 
We use a 1/2" ratcheting torque wrench...

The fill plug is in front of the diff output flange....
 
Belmetric is my go-to for bolts and washers. All the old wave washers get tossed and new ones installed. It is too cheap to make the change and the cleaning and re-plating process leaves a part that no longer has the holding power that a new product does.

I buy a good amount to have some on hand for the popular sizes.

Also, there is a source here for the original fasteners and parts on our cars that you may find helpful: The coupe parts manual
 
When in a similar situation...but not on my E9, I bought a cheap hex wrench ( avoiding using the term Allen so as not to trigger bad memories for you) then cut off a short segment that will fit in that little space and then fit it into a wrench and use that to loosen the plug. Loosen and spray with BP blaster or equivalent, then tighten a bit to get the internal threads coated, then remove the hex and wrench and finish removal by hand. I realize as you use this technique, the plug drops and then you get stuck and cannot remove the entire setup, thus the PB blaster and slight re-tighten and then remove by hand.
 
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