gruntus Posted November 26, 2006 Share Posted November 26, 2006 Hi Again, I asked a while ago what would fit from a Disco onto a defender 90. My 90 has drum brakes to the rear and I have been told yes the axle off a series 1 Disco will fit and is a very worthwhile conversion to do (thanks again Les and everyone else who replied). However......I was also told that the braking bias does change and may lock up on the rear under heavy braking. Sooooo.... heres the questions: 1) To change over the rear axle I presume (correct me if I am wrong) that the Disco and Defender rear axles (read as brake calipers) must be similar if not the same? 2) If so will I just need to change the pressure reduction valve (sitting under the master cylinder in the engine bay) to a newer type the same as those fitted on Defenders fitted with disks all round? 3) Which of the all wise gurus out there know what the the part number may be? (I am hoping flattery wil save me a bit of work , what a lazy git....) Thanks (again) in advance. Regards Grant Quote Link to comment Share on other sites More sharing options...
western Posted November 26, 2006 Share Posted November 26, 2006 3) Which of the all wise gurus out there know what the the part number may be? (I am hoping flattery wil save me a bit of work , what a lazy git....) 90 brake valve is NRC8215 upto chassis KA930455 no valve shown or listed for rear disc braked 90's no valve shown or listed on Discovery rear disc either. Quote Link to comment Share on other sites More sharing options...
Andy Posted November 26, 2006 Share Posted November 26, 2006 no valve i can think of on my disco. its probably the size of the calipers that control the spread of the braking force. Quote Link to comment Share on other sites More sharing options...
western Posted November 26, 2006 Share Posted November 26, 2006 90 rear calipers STC1265 [LH] & STC1264 [RH] Discovery same as above from rear axle number 28S 44172D or 32S 2119B Quote Link to comment Share on other sites More sharing options...
gruntus Posted November 27, 2006 Author Share Posted November 27, 2006 Thanks guys, Ralph (star player!) do you know what year the stated axle numbers would relate to? ....and is my crawling obvious ? Thanks again Grant Quote Link to comment Share on other sites More sharing options...
Guest diesel_jim Posted November 27, 2006 Share Posted November 27, 2006 Whenever i've fitted a disc braked axle to the back of my 90's ( done 3 now) and to mates vehicles, we've never fitted any kind of bias valve. the back end doesn't lock up and they all pass MoT tests no problems. literallty roll the new axle under the vehicle and bolt it up. job done. Quote Link to comment Share on other sites More sharing options...
gruntus Posted November 27, 2006 Author Share Posted November 27, 2006 Whenever i've fitted a disc braked axle to the back of my 90's ( done 3 now) and to mates vehicles, we've never fitted any kind of bias valve. the back end doesn't lock up and they all pass MoT tests no problems.literallty roll the new axle under the vehicle and bolt it up. job done. Thanks Jim, Can you confirm the year of the 90's? My 86 with the rear drums does have a bias valve fitted as shown on the PIC. Let me know your thought. Regards Grant Quote Link to comment Share on other sites More sharing options...
Ivan Posted November 27, 2006 Share Posted November 27, 2006 Grant As Jim says, I have an 87 90 and have just fitted a RR rear axle. Just bolted it in, fitted new dics and pads and it's fine. Sorry, forgot to mention mine has one of those valve thingies as well. HTH Ivan Quote Link to comment Share on other sites More sharing options...
gruntus Posted November 27, 2006 Author Share Posted November 27, 2006 GrantAs Jim says, I have an 87 90 and have just fitted a RR rear axle. Just bolted it in, fitted new dics and pads and it's fine. HTH Ivan Hi Ivan Thanks Just out of interest do you also have the pressure reducing valve fitted on yours? (as shown in the picture) Cheers Grant Quote Link to comment Share on other sites More sharing options...
Ivan Posted November 27, 2006 Share Posted November 27, 2006 See edited post. Yes I do. Cheers Ivan Quote Link to comment Share on other sites More sharing options...
gruntus Posted November 27, 2006 Author Share Posted November 27, 2006 See edited post. Yes I do.Cheers Ivan Great thanks a lot. Cheers Grant Quote Link to comment Share on other sites More sharing options...
western Posted November 27, 2006 Share Posted November 27, 2006 Thanks guys,Ralph (star player!) do you know what year the stated axle numbers would relate to? ....and is my crawling obvious ? Thanks again Grant Simply nope, can't tell axle yaers from the parts listing, both the above serial numbers are from Discovery original version, not the later Td5 variant. ....and is my crawling obvious ? Quote Link to comment Share on other sites More sharing options...
steve_a Posted November 27, 2006 Share Posted November 27, 2006 Discovery have a bias valve, pressure reducing valve PRC something, cylinder off a t piece under master cylinder on what is left of your inner wing. About £30 for a replacement (did it a couple of months ago). T piece sits on the line for the right hand caliper and the output from the pressure reducer feeds rear axle. My 90 has a disco rear axle, and even with all my tools and carp, the back is still liable to lock up. I don't know if the disco valve would help to be honest though, for the sameish price you buy a aleterable valve though which I would expect you can get to the right pressure. It has the same thingy as in the picture, which appears to do naff all to help. Having said all that, do the swap, lot less trouble than drums I think Quote Link to comment Share on other sites More sharing options...
LR90 Posted November 27, 2006 Share Posted November 27, 2006 Mine could lock up with drums on and I can still do it with a disk braked axle on the back so no difference. Do the swap, I was reluctant as I never had much bother with drums but was genuinely surprised at how much better the brakes and pedal feel now. Quote Link to comment Share on other sites More sharing options...
western Posted November 27, 2006 Share Posted November 27, 2006 Discovery have a bias valve, pressure reducing valve PRC something, cylinder off a t piece under master cylinder on what is left of your inner wing.About £30 for a replacement (did it a couple of months ago). T piece sits on the line for the right hand caliper and the output from the pressure reducer feeds rear axle just found this valve in EPC it's part number is ANR3194 from chassis [vin] MA081992 except Antilock Brakes or the earlier version is NTC6868L upto chassis [vin] LA081991 RHD - except Antilock Brakes Quote Link to comment Share on other sites More sharing options...
steve_a Posted November 27, 2006 Share Posted November 27, 2006 that's the puppy, good ol NTC6868L, just a wee tube that makes you wonder WTF it will do for you. I replaced mine because it started to leak. Suggest you have a look at something like these, cheap and may make a big difference to performance http://search.ebay.co.uk/search/search.dll...rake+bias+valve Quote Link to comment Share on other sites More sharing options...
gruntus Posted November 28, 2006 Author Share Posted November 28, 2006 Suggest you have a look at something like these, cheap and may make a big difference to performancehttp://search.ebay.co.uk/search/search.dll...rake+bias+valve excellent thanks, didn't even think about that and didn't realise they were so cheap!! guy across the road builds rally cars and spraffs on about setting the brake bias ratios to his own taste. and now it makes complete sense!! Thanks all for your comments (encouragements) I really appreciate it. Now to find a cheap (but good) rear axle............... Regards Grant Quote Link to comment Share on other sites More sharing options...
JST Posted November 28, 2006 Share Posted November 28, 2006 i have fitted 4 disc rear axles to 90s that previous had drums and fitted them straight in without adjusting any bias, no problems to date. RR axles fit as well. dont you need to change the prop flange on some of the disco axles to fit the def 4 bolt prop setup? Quote Link to comment Share on other sites More sharing options...
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