Disclaimer: These articles and procedures are examples of how and what can be done. These all assume the use of proper tools and the M535i SIG and I take no reponsiblity for any incorrect information posted on this page. If you are not comfortable in undertaking any automotive repair, take your car to a qualified BMW mechanic. Otherwise use this information at your own risk. Like the copyright says any duplication of this information with out the explicit permission of the M535i Special Interest Group & Registry is prohibited. If you run into any specific problems please email me through the link at the bottom of the page and I will try to assist you as best I can.

I have E28 air in my car. It works really well. I had to make some custom brackets for the condessor in the front of the car at which point I used the E28 aux. fan. The only down side is you have to run custom lines and it is hard to find custom metric lines. I am currently working on that. If your car did not originally come with AC you will also need the AC center console. I am using an E28 evaporator, compression, reciever/dryer, and condensor. You will have to do some minor electrical work to get everything to work right, but it is a lot colder than coupe AC, and you also can use R134A and not have a problem with not finding freon in a few years.

I suggest getting yourself e28 rear window motors. They bolt in with only minor modifications to the front doors. The rears just drop in. As for powering them, some who are adventurous wire them up to the e9 wiring, but I would suggest using the whole power window harness out of a 5 or 6 and wiring it in to the coupe power source and fuse. I have a complete e28 535i wiring harness in my car so I really can't help you with modifying the wiring because my window motors just plugged in. I would suggest though to that you use a modified 6 or 5 series power window harness. As then you will not have to so much rewiring.

In the head, on top of the cam, there is an oil sprayer bar that directs oil to lubricate the cam and rockers. The oil spray bar bolts are hollow bolts through which oil passes through, into the oil sprayer bar. Now, these bolts tend to come loose in time from vibration. This can happen in as little as 20k miles, or as long as 150k miles, there is really no "set" mileage that this happens.

BMW has issued a new bolt to fix this problem. Really, what it is is the same bolt with a tad of locktite on the threads. But it is a new partnumber and the old bolt (with no blue locktite) and the new bolt are differentiated by a round circle engraved in the head of the new bolt. The part number for these bolts is 11 42 1 738 621.

Any good (i.e. knowledgable) BMW mechanic should know about this problem on M30s. And whenever you get a valve adjustment (which should be every 15k miles or 1-2 years), the mechanic should check the torque on those bolts. So long as you do that, you should have no problem. Even with the "old" bolts.

BTW, a valve adjustment on these cars should run around $100, give or take. This includes a new valve cover gasket. That is the only repair that I'd take, and have taken, my car to a mechanic to. You really need to get a "feel" to adjust the valves on M30s. It's an art in itself. But if you do do it yourself, you have to do with the engine stone COLD, because otherwise you won't do a good job. (Leave it sitting overnight). Oh, and you will also need a method to turn the engine (remote starter, big socket and wrench to turn crankshaft rotating nut, etc).

You get a much better engine management. Better engine management means more power and better reliablity. Now, most people are not planning on using an E9 as a daily driver, but it is always nice to be able to hop in the car when you want and fire her up for a drive. Motronics allows for this, and while I am not saying that L-Jet is unreliable, it is much more difficult to find parts and is not as reliable as the motronics. I personally think that there is really no point in doing anything other than motronics, unless you are not doing a full restoration. With motronics you HAVE to weld brackets into the engine bay and well that just isn't good, unless you are going to be painting the car after that has been done.

I would first look at your diff mount. If it is bad, it will cause the diff to sag which will contribute to poor rear suspension geometry as well as putting excess strain on the universal joint in the driveshaft. Then I would want to check to see if the half shaft ends are still round. They generally oblong which can cause a low speed vibration. Then I would move to the guibo. Check to see if that is good. If you see cracks it must be replaced. Then look at tranny mounts. If they are broken that will cause the tranny to move around under hard load causing a vibration. Also check to make sure the center bearing is preloaded correctly. If it is, it should be deformed slightly towards the front of the car. Also make sure the motor mounts are still good. With all of this checked and/or replaced, if you still have the vibration then most likely you will need a new driveshaft.

A clunking in the front suspension, can be a couple of things. First I would think that it would be the upper strut bearings. The way to check this is to find a bump on a secluded road and have a friend drive the car very slowly over the bump with the hood open and your hand on the upper strut bearing. If you feel the clunk in your hand then it is most likely either the upper strut bearing or the shock. The next thing to look at is whether the bearing is deforming or the strut is moving and the bearing is not. If the rubber of the bearing is deforming then you have a seized strut. If the strut moves and the bearing does not deform then I would suggest replacing the bearing. The clunking can also be caused by very badly worn ball joints, but I doubt that if you have no shimmy problems.

I use the e23 front calipers and the 3.0csi rear calipers. The e23 front calipers have only a single input into the caliper and use vented rotors from the 3.0csi. The reason I use those calipers is because I use the E28 535i(non-ABS) master cylinder. I have re run lots of lines, and basically there are 2 outputs from the new master cylinder. The front one goes to a T fitting that runs one line to the passenger front and the other to the driver front. Then the line that comes out of the back of the master cylinder runs to a straight through connector that allows you to connect 2 hard lines together. Then I run 1 long line to the back of the car. Unlike the coupe I ran this line like every other BMW after which is down the driver's side rocker. I then have a T fitting in the back of the car that splits the fluid to both trailing arms. The master cylinder has the brake balance already in it. So there is no need to use the coupe balancing unit. Also there is no need to do the cross braking system, as the front and rear are now separate systems that if you loose fluid in one, you still have fluid in the other. I am also using E28 M5 stainless lines.

As our car age, various things go wrong that you would not expect to have happen on a new car. Some of these problems most DIYers don't think twice about attempting, but there are some things that most people shy away from. For example, the average DIYer will have no problem doing a brake job, but when they find out that they have a stuck caliper, many just think that their only option is to purchase a remanufactured unit through a dealer or Maxamillian. Well, this is not the case, BMW and Maxamillian sell what are known as caliper rebuild kits. These kits come with all of the necessary rubber O-rings to rebuild a caliper. Now lets say you have a stuck caliper on your coupe, and you have decided that you want to attempt to rebuild your own caliper(Which is not something I suggest to an inexperieced DIYer).

First, you need to remove the outer dust boot. Once this is removed you must remove the piston out of the caliper. To do this you can use one of three ways. The first one is to just push on the brake pedal until it pops out. This is accomplished by having the rest of the brakes on the car and working correctly, then you unbolt the questionable caliper from the trailing arm or strut tube and then you remove the pads. Once this has been done, then you have a friend push on the brakes. You will see the piston start to move. Now you will want to have a catch can under the caliper because as soon as you get the piston out the brake fluid that was in the reservoir and in the brake line will come out. Be careful to catch the piston when it pops out because you don't want to damage it. This is an easy way of removing the piston, but you will find that you can only do one caliper at a time and then you have to bleed the system before you can do a second one. It is also difficult to rebuild the caliper with it still attached to the brake line. So the second and third way involve removing the caliper completely from the car, this is also the preferred way to rebuild a multi-piston caliper like those lovely E28 M5 calipers that you just bought to put on your car. The second way to remove the pistons is to used compressed air. In the port that the brake line screws into, you pump compressed air into the caliper and this will push out the piston. This is the preferred way to do this step. Now, some of us who have rebuilt quite a few calipers have found that the fluid, and the compressed air won't loosen the piston. Well don't worry, there is one more way of removing the piston. This involves using a vise grip and a vise. First you clamp the vise grip to the piston with as much force as you can. Now remember, you only want to clamp it to the unmachined surface. This is the area that is in direct contact with the pad. You will notice that it has a small diameter then the rest of the piston. Once you clamp the vise grip on, then you place the handle of the vise grip into the vise and tighten it down. Now you need to grab the caliper with both hands and try to rotate the piston in the bore. This is made easier by plenty of releasing fluid. Once you have gotten it to rotate in the bore then you need to carefully pull the piston out of the caliper by pulling and rotating at the same time. The reason why you do both at the same time is because you want to make sure that you don't cock the piston in the bore. If you cock the piston you will find that you can damage the caliper bore. Now, people with the M5 multi-piston calipers will be asking, how do I get the vise grip on the piston. Well what you need to do is unbolt the two halves of the caliper. There are four bolts that hold the caliper together. Once you have removed these four bolts put them in a safe place because they are no longer available from BMW. You will also notice that there are two spacers, and four small O-rings. Non of these parts are available from BMW anymore, so it is important not to lose them. I suggest that once you have the small O-rings out that you soak them in NEW brake fluid. WHEN REBUILDING CALIPERS ONLY USE NEW BRAKE FLUID!

Now that you have the piston out, you open your rebuild kit. There is a larger rubber O-ring in the kit. This O-ring is actually placed in a groove in the caliper bore. You need to remove the old O-ring. Then it is time to clean out the caliper. This is easily done with compressed air, but can also be accomplished by plenty of brake parts cleaner. Once you have cleaned out the caliper you need to inspect the bores. If you see any rust in the bore, you will need to clean it out. This is done by carefully and I mean carefully using some emery cloth on the rust spot. Now that you have gotten rid of the rust spot, you need to inspect the bore for any scoring. If there is some slight scoring you can probably smooth it out with the emery cloth, if there is deep scoring you will need a new caliper. Once you have cleaned and inspected the bore you will need to coat it thoroughly with brake fluid. Then soak the new rubber O-ring in brake fluid and install. Make sure that the seal is not twisted in any way. Now you need to clean any rust off the piston and also inspect it for scoring marks. Once you have cleaned it and inspect it, you can cover it in brake fluid and carefully reinstall it in the bore. You must be very careful doing this because you need to make sure that you don't cock the piston. But unlike removing the piston you cannot rotate and install the piston at the same time. You need to push the piston in by hand. You will know if the piston is cocked because it will become very very difficult to install. Now remember you will need to get the piston by the rubber O-ring so don't mistake getting the piston by the O-ring with it being cocked. Now that you have the piston back in you need to put on the new dust boot. Once you have that on, the piston caliper is back together. And for those with the M5 calipers, you will need to bolt back together the two halves of the caliper. Make sure to clean everything and wet it down with break fluid. Also make sure you reinstall all of the small rubber O-rings and make sure not to pinch them. Once everything is back together, I suggest for your floating caliper to use high temp. wheel bearing grease on the guide bolts. This will ensure smooth operation of the caliper. Bolt the caliper back onto the car and bleed the brakes.

Now you have successfully rebuilt your caliper and probably saved yourself at least $100 for each caliper.

*The E28 M5 caliper is just like any other multi-piston BMW caliper and so the techniques can be applied to all multi-piston BMW caliper.