Showing posts with label 323i Rear Brakes. Show all posts
Showing posts with label 323i Rear Brakes. Show all posts
Saturday, May 26, 2012
Monday, April 9, 2012
e30 calipers on e21 323 trailing arms?
conversation on bfc regarding the upgrade on an upgrade...after an owner swaps out 320i trailing arms for the disc brake counter part from a 323i...an additional disc brake upgrade is possible...specifically, removing the 323i calipers, drilling out the threads, permitting the nuts, and bolts required for the e30 disc brakes...the following is a discussion on bfc...
e30 calipers on e21 323 trailing arms?
Does anyone have any specific information on
this swap? I've seen it posted like its a direct bolt on but the '89
325i calipers I have are very different from the stock 323i calipers.
They mount from different sides of the bracket. Has anyone actually
done this swap that can give input?
Thanks, Steve.
Thanks, Steve.
I haven't done it, but it's a matter of drilling out the threads on one side to allow for the different mounting position. jrcook
My 323 trailing arms are disassembled now. I will have to reinstall the
bearings, axles, hub, etc so I can see how everything lines up. But,
if the 325 caliper mounts the same as the 323, the caliper bracket will
need more than just drilling the threads out. It is machined to mount
on the opposite side. The side to mount like the 323 bracket is just
the rough casting and has a rib which is higher than the areas around
the mounting bolt holes that would prevent it from sitting flush. It
looks to me like the bracket will have to be machined flat for proper
mounting. Can anyone verify this? I will try to check all this this weekend if I can. Steve.
I just did this conversion took pictures to do a write up, I believe I have the pictures on my digital camera that is with me, but my notes are home and I'm away on business. Below is a link for reference, that I used. I believed my calipers were from an 87 e30, holes lined up perfectly, I also believed that I drilled holes out with 13/32 drill bit. I used my drill press with 3" roloc disc to grind the carrier down, this gave me a machined like finish. I also had to cut the back-plate were the piston goes. Final touch was I bought some UUC brake lines. I'll do a write up this weekend when I'm home, I'll have access to my notes for exact size. Also I'll see if I can send pictures in the mean time. dhlthr
Additionally, the E30 brake hoses work fine on the E21 and bolt right up. I have done this now to both of my E21 and feel its better way to go. The E30 brake calipers offer more options for rear brake pad compounds and general availability.
I used a 13/32" bit. I then screwed the carrier to a board jig that would keep it flat and used drill press and grinding disk to grind area flat. I test fitted with rotor on trailing arm a couple of times to make sure that I did not over grind. When I was happy that rotor was center of carrier I was close to .580 width.
Apparently, Rob at BavAuto says this swap is as easy as pie, and a great upgrade. All that's needed is you have to drill a little. jjgbmw323
I picked mine up from junkyard, was told they were from an 87 eta. Don't know if there is a difference, but I believe all e30 caliper carriers are the same and have a 2.25" bolt spacing which is what our trailing arms have. I bought a rebuild kit and rebuilt my calipers as well (cheap and easy). dhlthr
The teflon sleeves are the newest trend, I have seen them in clear and red but don't remember if they were for BMW. I don't know of anyone making the teflon coated for 323i because of the banjo bolt. I had a set of bavauto with the 323i calipers. dhlthr
I went to the bone yard today&picked up a few pairs of e30 rear calipers, went home & modified a pair&got them mounted. These really are a much better designed caliper than the e21. The pad surface area really isn't much bigger, but rather than being a rectangle, the pads a are shaped in a trapezoid, so the outside edge is much bigger (more torque where it's needed). I found that I didn't need to modify my backing plate at all as long as you modify the caliper correctly. Jester323
I can identify only one
style of rear caliper for e30's. All of the calipers checked have 2.25" inch mounting centers, from E30 323i calipers
to E30 325ic calipers (earliest and latest, best I know). All of the larger series cars and later rear calipers I've found had a 3'' inch mounting centers (E36, E28, E23, etc)...
Source - http://s37.photobucket.com/albums/e53/dhlthr/
Source - http://forums.bimmerforums.com/forum/showthread.php?t=966135&highlight=brake+cooling+ducts&page=5
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| the e21 323i rear brake caliper |
Tuesday, January 17, 2012
Monday, November 7, 2011
323i Rear Disk Brake Dis-Assembly (Part 2)
a divorce forced me to sell the house i have lived in for over 20 years, this all took place while during the dis-assembly of the 1977 e21 that my son and i drove home from california where the car was raised and lived it 'sheltered' life...in the mist of this dis-assembly as you can image i have cardboard boxes and plastic containers filled with bmw stuff...my son and i loaded the car onto a car hauler several weeks ago and moved it to its new home...a 1 small one stall garage...in that move i have misplaced more than i've wanted too....but after some settling last week i jacked the car back up and placed the frame on jack stands in an attempt to finish the required work on the sub-frame, drive train, brakes, and wheel bearings...over the last few days i began to focus on the disc brakes from the newly restored 323i trailing arms...the motivation for restoring and upgrading to the 323i trailing arms was 2 fold...like the earlier model e21 the 323i has an upgraded braking system to accommodate the larger engines...in the case of the 323i another upgrade that is not commonly discussed is the increased size of the wheel bearings...this becomes important to tuners because many of us utilize larger wheels on our cars...and the jump from 13' wheels to 15" wheels in theory and practically increase the pressures applied to the wheel bearings as you can imagine..i replaced the wheel bearings, grease seals, and associated parts on my 323i trailing arms...the pictures below are of the 323i disc brakes...(but just for the record, i am of the opinon that wheel bearing increases are NOT a reason to upgrade to 323i trailing arms...the rear disc brakes are however are a good reason if you don't want to weld in the appropriate plate/brackets to hold disc brakes...
The picture above is a rear 323i disc brake that came with the 323i trailing arms i bought...these brakes are in reasonably good condition as you can see in the pictures...notice that the rubber piston seals are intact and still in good working order and could have been installed without replacement but while they are off of the car it makes sense to restore them...
if you look closely at the brake caliper in the picture above you may notice that the retaining spring that holds the 2 halves together has been broken off...this happened as i attempted to remove the clip...i broke 2 tapered punches trying to free the spring...usually these springs just slide into the holes and are held in place by the spring's pressure...this one was a BEAR...
...in the picture above you can see the backside of the caliper with the broken spring still in place...
...the caliper was taken apart...and as you can see...that's the first broken punch tip at the center!!!
...in my opinion, one of the most important aspects to rebuilding disc brakes is the condition of the brake piston, and the walls of the sleeve...in the case of this brake the piston is smooth, no scaring or scoring of either the piston walls, or the piston itself...for my purposes that means this brake is rebuildable and not scrap...
...as you can see...the 35 yrs or so of service has allowed sentiment, and crud to settle in the closed system...i am in the truest sense of the word only a weekend mechanic and my "poor boy" ways learned as a kid in my dad's garage never took things like this seriously...for me this was a lesson in maintenance...the interior walls of this disc brake will NOT be honed because the walls are in perfect condition as is the piston...with the new seal kit the rubber piston ring will seal nicely and fit/slide smoothly...
...this is the best picture i could get of the interior walls of the sleeve...notice the retention ring, the rubber seals have been removed...crud is still in place however!
...after dis-assembly and cleaning the caliper with solvents, a wire brush, and a wire wheel in preparation for paint, i fit the brake back onto the trailing arm bracket. notice the NOS dust shield...new parts are sexy!
...if you look at this picture closely...you'll see this was my best attempt to fix the retaining spring stuck inside the brake caliper...i thought i would be "smart" and put the caliper in my drill press, squared, and level i tried drilling out the spring fragment...what i DID NOT anticipate was the differences in metal hardness...when i tried drilling the spring out the drill bit shifted and the result was that the drill bit slid into the caliper avoiding the harder spring steel...thus creating another hole in the caliper!!! ugh...unanticipated result for sure...but confirmed i'm only an amateur...
...this picture illustrates the "second" hole that resulted...i am anticipating using that hole to install the new retaining clip...it will be tilted off angle somewhat and certainly not what i wanted...but...
...cleaned and painted...
...second half of the caliper cleaned and painted...is it my imagination or do those holes seem to stick out in this picture...lol...
..what is pictured above is the rubber boot included in the 323i rear disc brakes rebuild kit...specifically, the rubber seal inside the brake sleeve, the piston, the rubber boot, and the outer snap ring protecting the piston and associated parts for being contaminated with dirt and grit which eventually will deteriorate the inner rubber seal between the piston inside the brake...
...believe it or not getting this rubber boot to fit correctly down into the piston was the most difficult aspect of this assembly...
...finally, the boot fitted down inside the piston and the snap ring is installed...
...the pads were fitted to the brake pad mounting pins (seen unseated)...
...ok, the first one is finished...but, as you can see i didn't have the vent/airator but its on order.
Tuesday, November 1, 2011
323i Rear Disk Brake Dis-Assembly
Because of the rarity of the e21 323i caused by low production numbers, and even lower import numbers parts for the e21 323i rear brakes are expensive..many have suggested simply upgrading to the e30 rear brakes and there is great reasons to do that, particularly parts availability. on several forums i have also recently discovered that with a 2.25 inch trailing arm spacing you can use VW type 1 calipers which have a built in handbrake. (e21 323i early/late trailing arms have 2 different spacing for the brake calipers, earlier model seem to utilize the 2.25" spacing, the later models utilize the 3.0" spacing.)
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| i purchased a set of 323i trailing arms with the disk brakes included, upon arrival, i removed the rear brakes. during the dis-assembly one of the tension springs had frozen in the caliper and would not come out after repeated hits with a small punch from the back side...ultimately, the spring broke after being subjected to my vise grips!! |
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| As you can see in the photo above, a spring broke off in the caliper, even after being soaked with penetrating oils...the 323i brake calipers are made in two pieces and those pieces side together. the photo above is immediately after the spring broke off in the retaining hole. this required drilling out spring steel...ha! not an easy task... |
About the 323i rear brakes
There is one system on the E21 323i that is completely unique among all other BMWs. All E21 models except the 323i used drum rear brakes. Rear disk brakes were only used on the 323i. Besides that, many of the parts used on the 323i rear brakes were not used on any other BMW model. This can make parts availability a bit troubling. This page contains all I've been able to put together about servicing and upgrading the E21 323i rear brakes.
The easy stuff first - the rear rotors (discs) are the same as the ones used on all E30s with rear discs except the M3. So those rotors are easy to find, and not expensive, either, unless you pop for the cross-drilled and/or slotted ones. Like most BMWs, the parking brakes are miniature drum brakes contained inside the hub area of the rear rotors. They seldom wear out, and I haven't researched whether any of those parts are common to other models. I'll add that information to this page at a later time. I do know that the parking brake cables are specific to E21 323i.
The drum brake E21s use four flexible brake hoses, one to each front caliper and one at the pivot of each rear trailing arm. The 323i uses six hoses, four of which are identical to the drum brake car's hoses. The remaining two hoses connect directly to the rear calipers. These hoses attach using banjo bolts, which make them different from any other BMW brake hose. Their rarity - of course - makes them rather expensive, around $50 each. A good alternative is to get a set of stainless braided teflon hoses from Korman (the only supplier I've heard of who has them for E21 323i). At last check, the entire set of six hoses was less than $100, which means you get all six high-performance hoses for the price of the two rear stock ones. When I added those hoses with no other changes (fresh DOT 4 fluid, of course), the brake pedal felt noticeably firmer.
There were two different rear caliper types used on the E21 323i, early (through ~78) and late ('79 and up). Both styles are similar and were only used on this model. Similarly, the rear pads are specific to these cars and are not going to be easily acquired locally. There is a pad wear sensor on the right side, which is the same one as is used on the front of all E21s and many other '70s and '80s BMW models.
Factory pads (generally Texar) are still available from numerous sources, but aftermarket pads can be a bit tougher to find. Korman lists Ferodo in their catalog, but I don't know if they are really available. BMP Design had PBR (formerly Repco) Deluxe and MetalMaster rear pad sets in stock during the Summer of 2000.
Seal kits to rebuild the calipers are still available from BMW in Germany, as are the pad hardware kits. If your local dealer can't help you with them, Maximillin Importing can. But note that (at least for the later style caliper) BMWs part references (both CD-ROM and the old fische) call for only a single kit to rebuild both calipers - not so, you need one kit for each caliper! The calipers themselves are still available new, but are rather expensive (~$250 each).
Another option is to fit E30 rear calipers and pads. This makes parts availablity much simpler, everyone knows what brake parts an E30 325e takes. Plus the E30 pads have more surface area, and in theory should perform better. But there are some modifications needed. You will need the rear flexible hoses from an E30, and the mounting holes are not a direct match. More information on this conversion will be added later.
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The easy stuff first - the rear rotors (discs) are the same as the ones used on all E30s with rear discs except the M3. So those rotors are easy to find, and not expensive, either, unless you pop for the cross-drilled and/or slotted ones. Like most BMWs, the parking brakes are miniature drum brakes contained inside the hub area of the rear rotors. They seldom wear out, and I haven't researched whether any of those parts are common to other models. I'll add that information to this page at a later time. I do know that the parking brake cables are specific to E21 323i.
The drum brake E21s use four flexible brake hoses, one to each front caliper and one at the pivot of each rear trailing arm. The 323i uses six hoses, four of which are identical to the drum brake car's hoses. The remaining two hoses connect directly to the rear calipers. These hoses attach using banjo bolts, which make them different from any other BMW brake hose. Their rarity - of course - makes them rather expensive, around $50 each. A good alternative is to get a set of stainless braided teflon hoses from Korman (the only supplier I've heard of who has them for E21 323i). At last check, the entire set of six hoses was less than $100, which means you get all six high-performance hoses for the price of the two rear stock ones. When I added those hoses with no other changes (fresh DOT 4 fluid, of course), the brake pedal felt noticeably firmer.
There were two different rear caliper types used on the E21 323i, early (through ~78) and late ('79 and up). Both styles are similar and were only used on this model. Similarly, the rear pads are specific to these cars and are not going to be easily acquired locally. There is a pad wear sensor on the right side, which is the same one as is used on the front of all E21s and many other '70s and '80s BMW models.
Factory pads (generally Texar) are still available from numerous sources, but aftermarket pads can be a bit tougher to find. Korman lists Ferodo in their catalog, but I don't know if they are really available. BMP Design had PBR (formerly Repco) Deluxe and MetalMaster rear pad sets in stock during the Summer of 2000.
Seal kits to rebuild the calipers are still available from BMW in Germany, as are the pad hardware kits. If your local dealer can't help you with them, Maximillin Importing can. But note that (at least for the later style caliper) BMWs part references (both CD-ROM and the old fische) call for only a single kit to rebuild both calipers - not so, you need one kit for each caliper! The calipers themselves are still available new, but are rather expensive (~$250 each).
Another option is to fit E30 rear calipers and pads. This makes parts availablity much simpler, everyone knows what brake parts an E30 325e takes. Plus the E30 pads have more surface area, and in theory should perform better. But there are some modifications needed. You will need the rear flexible hoses from an E30, and the mounting holes are not a direct match. More information on this conversion will be added later.
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