RedbeardRacing Posted January 22, 2023 Share Posted January 22, 2023 I noticed a few drops of gear oil inside my rear left rim while I was unloading the car from about a 2 month winter nap. Looks like I'm doing axle seals, and figured while I'm in there I can change the gear set too. The car is 2003 birkin, any guesses on what Toyota live axle rear end assembly they were putting in them back then? Or just a quick measurement to see what it is from the sides? I have a couple photos from when I had the tray out too. Thanks all. Link to comment Share on other sites More sharing options...
RedbeardRacing Posted January 22, 2023 Author Share Posted January 22, 2023 One more picture. Link to comment Share on other sites More sharing options...
MV8 Posted January 23, 2023 Share Posted January 23, 2023 That axle is a Borg Warner 68 used on Aussie Datsun B210s. http://datsun1200.com/modules/mediawiki/index.php?title=Borg_Warner_Differential 2 Link to comment Share on other sites More sharing options...
RedbeardRacing Posted January 23, 2023 Author Share Posted January 23, 2023 Thanks, you seem pretty confident on that one! My paperwork shows a quaife diff in there, so I'd imagine I can find another gear set for it. And that page had all the bearings and seals. I wonder why the previous owner thinks it's a Hilux rear? Link to comment Share on other sites More sharing options...
MV8 Posted January 23, 2023 Share Posted January 23, 2023 Articles on the birkin mention a toyota axle and maybe they switched to that at some point. If you go to quaifes site, they list a diff under the caterham as a BW68 plus the ridges on top of the housing make it unique. Are you looking for a more highway friendly, numerically lower ratio? Link to comment Share on other sites More sharing options...
RedbeardRacing Posted January 23, 2023 Author Share Posted January 23, 2023 If you look at my previous post history I was looking at changing the gear set in my t9, it is geared very high. 2.39 first. And I was leaning more toward a 4.30 or 4.56 rear gear versus my current 3.90 to get some more bottom end pep. I'll go look at the quite site now, thanks again. Link to comment Share on other sites More sharing options...
RedbeardRacing Posted January 23, 2023 Author Share Posted January 23, 2023 I see the diff on the quaife website. Bw m68, so now I need axle seals and ring and pinion gear options that will fit it. Link to comment Share on other sites More sharing options...
MV8 Posted January 23, 2023 Share Posted January 23, 2023 I think it would hard to find if it was ever available for such a small diff. Part of the problem is that as the numerical ratio increases, the thickness of the teeth decreases while at the same time the multiplied torque increases. You might consider an axle conversion to an equivalent that came with a 4.30 ratio (maximium), like the Toyota 10 bolt 6.7" ring gear axle used in dwarf cars, just not severely shortened on the right side. For a used axle, look at 82 and older corona, 84-87 corolla GTS, 74-79 SR5, 71-85 celica ST and GT. I expect there are parts available for these for racing. They came with either two or four spider gears and an open or limited slip. A Ford 8 inch is a common axle here that is built like the famous ford 9 inch only smaller and lighter. I think it was used in the H&S Seven. Link to comment Share on other sites More sharing options...
BirkinBernie Posted January 24, 2023 Share Posted January 24, 2023 Hi all. I built my Birkin from the basic "BIY" kit in 2000/2001 and it has the same axle as Redbeard's. I installed a Quaife in my rear axle when I built the car. Quaife has a specific listing in their catalog for the solid axle Birkin from that era. We were told by the Birkin factory in South Africa that the rear axle was a newly manufactured unit as used in a Toyota Hilux minivan manufactured and sold in South Africa. The only ratios I have ever known of for those rear ends were the two that came in solid axle Birkins. 4.11:1 until early/mid 2000, then 3.89:1. My kit landed in the US in September of 2000, and it has a 3.89. The first two pics below are the original diff carrier that came out of my Birkin, replaced by the Quaife. If you zoom in on the first one you will find the number "68" in the casting. Hmmm. MV8 - where did you get the info that this is a BW axle? The axle housing castings do not have the name Borg-Warner in them, fwiw. Also, the rear cover looks different than one in a pic on that page you linked. The pictured one is deeper. This is fascinating. Incidentally, the Quaife catalog still lists Birkin as "Quaife Borg Warner M68 Axle ATB Differential". It also says "In Stock" which is shocking!: https://shop.quaife.co.uk/shop/atb-differentials/quaife-borg-warner-m68-axle-atb-differential/ Their listing has a link to a "technical spec" drawing. I dug up the old diff center section, and the dimensions and spline count of my old one appear to match the current Quaife drawing. So, maybe we all missed the boat years back - I have never seen the Birkin diff identifed as a Borg Warner - Quaife's catalog in 2000 made no mention of Borg Warner in relation to this diff. In late 2000, before I dropped the big bux on a Quaife, I sent one of these center sections (borrowed from the importer Dick Brink) to Toyota Racing Development in California on the off chance they could identify it and provide a more cost effective LSD. They passed it around to their engineers, and nobody had ever seen one like it. Maybe it being a Borg Warner explains that. FWIW, the Quaife is a fantastic unit. I consider it table stakes on a solid axle Birkin. I drove one with an open diff and it wouldn't put power down at all. And the Quaife install was a breeze - no change to the setup and the gear pattern was perfect. Please share whatever info you dig up! This is of great interest. I just replaced an axle seal on my Birkin - Tom gave me the part number - it's a Timken 472826. I got them at a local bearing shop. Happy Motoring! 1 Link to comment Share on other sites More sharing options...
RedbeardRacing Posted January 24, 2023 Author Share Posted January 24, 2023 The rabbit hole gets deeper. Thank you for the info. 1 Link to comment Share on other sites More sharing options...
MV8 Posted January 25, 2023 Share Posted January 25, 2023 1 hour ago, BirkinBernie said: MV8 - where did you get the info that this is a BW axle? The axle housing castings do not have the name Borg-Warner in them, fwiw. Also, the rear cover looks different than one in a pic on that page you linked. The pictured one is deeper. This is fascinating. The housing ribs on top of the center section are unique to this axle but I agree, the cover is shaped a little differently for the datsun axles pictured. It may be different for the toyota van applications. I suspect there was some sort of trade agreement with Datsun and Toyota in order to sell their products in South Africa that was satisfied by locally sourced axles. Link to comment Share on other sites More sharing options...
MV8 Posted January 25, 2023 Share Posted January 25, 2023 Based on what you want, I'd consider shelving the existing axle as-is and adapting a 90's or newer suzuki sidekick/geo tracker rear axle for several reasons. The pros: 1) The width should be close to what you need as-is. 2) The ring gear is a bit larger than the m68 for stronger gear sets (6.7" vs. 6.9") 3) This axle comes with 4.30, 4.62, 5.12 and 5.37:1 gear sets (4.62 strongest with the fewest ring teeth). 4) A torsen type diff is available for about $650. 5) Despite being considered weak for a 4x4 with very large od tires, it should be a little stronger/heavier than what you have. 6) The drop out diff carrier/pumpkin is easily setup on a bench. The con: The axle uses a very large, common 4x4 truck 5 bolt circle and hub but adapters are available. The adapters would increase the axle width about two inches. I have a 90s 2 door, 2wd convertible tracker I converted to an s10 v6 and 700r4 with an open 5.12 axle and 235-60-16 tires on grand vitara wheels. Let me know if you'd like any measurements. The 90's axle is a three link where the 99 and newer is a 4 link with a panhard bar, but you'd be cutting everything off to duplicate the birkin brackets. This is my installed axle and my 4.30 diff with a couple web pics of the axles. 1 Link to comment Share on other sites More sharing options...
IamScotticus Posted January 26, 2023 Share Posted January 26, 2023 The RX7 GSL is a favorite 1 Link to comment Share on other sites More sharing options...
RedbeardRacing Posted September 30, 2023 Author Share Posted September 30, 2023 Time to revisit this topic. The original leak I thought was the axle turned out to be the brake caliper fitting. Crisis averted. But here we are 8 months later and after my first cruise post Texas summer. I have drips again on both sides. One is brakes and one is axle. I already have parts on the way from Tom. Seals and bearings. And as mentioned before I did all the digging I could do and there are no other ring and pinion options for this M68 setup. I have the quaife diff and that's all the upgrade I am going to get. So my questions are, anything crazy to know in advance of this diff and rear end service? Would anyone know where to find carrier bearings if I need them. The car only has 15k miles but I'm sure a lot of them are spirited, and it's 20 years old now. So might as well do them while I am in there, if needed. I am also going from the Volkswagen rear brake setup to the 1990 crx hf in order to clear smaller wheels for autox. Tom said they should bolt up, just on reversed sides and I'll have to open the rotor's center up to clear. Any input on that is welcomed too. Thanks in advance! Link to comment Share on other sites More sharing options...
MV8 Posted September 30, 2023 Share Posted September 30, 2023 The bearings and races should be marked/etched with part numbers that can be cross-referenced. Sounds like you are using '90 HF front rotors on the Birkin rear hubs (appears the '90 CRX had only one rotor for the rear for all sub-models). Use a lathe to open up the rotor pilot to fit so it will stay centered and not wobble. 1 Link to comment Share on other sites More sharing options...
RedbeardRacing Posted October 2, 2023 Author Share Posted October 2, 2023 Tom said to use a 1991-2002 escort rotor, and open the center. Not sure if it is different from the CRX. Brakes Older Live Axle (1).pdf Link to comment Share on other sites More sharing options...
MV8 Posted October 2, 2023 Share Posted October 2, 2023 That makes sense. Yes, the escort rotors are different. Link to comment Share on other sites More sharing options...
BirkinBernie Posted October 4, 2023 Share Posted October 4, 2023 On 9/30/2023 at 9:57 AM, RedbeardRacing said: "So my questions are, anything crazy to know in advance of this diff and rear end service? " Nope. I replaced a rear wheel seal a few months ago - a straightforward repair. Once I got the brakes and bearing retainer off, I used a cheap slide hammer from Chairman Mao's Tool Store that had a "hook" attachment to hook the edge of the flange and pop the axle out. The rest is self evident - I don't even remember the actual seal replacement. I would be shocked if the carrier bearings are damaged unless it has been run low on oil. I have never heard of anyone encountering that - especially with only 15k miles. When I built my car I called Quaife and asked what kind of oil the LSD needed. They said just use the standard lube - NO LSD additives should be used. Happy Motoring! 1 Link to comment Share on other sites More sharing options...
RedbeardRacing Posted October 23, 2023 Author Share Posted October 23, 2023 Well shit. The ID of the hat on the escort rotor is 4.88" the axle hub face is about 5.25" If I clearance it enough to fit I'll basically cut the hat clean off. It's the same part number for all years between 1991-2002. I expected to clearance the smaller hole on the top. But didn't expect this large interference on the axle hub face. Link to comment Share on other sites More sharing options...
RedbeardRacing Posted October 23, 2023 Author Share Posted October 23, 2023 Plot twist I found a box of rotors that came with car when I bought it. They are dimensionally the same as what is currently on the car. 1/8" taller and 1 MM thicker than the escort rotor. I'm thinking I can make those work. Don't see why I couldn't unless the thickness difference won't fit in the Honda caliper Link to comment Share on other sites More sharing options...
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