s99sdp Posted August 2, 2020 Report Share Posted August 2, 2020 I've got a leak thats getting worse so its time to change the seal on my rear diff. I've found someone to do it, could someone point me in the direction of what I need to order and where from so he's got everything he needs to proceed? It's for my 1970 Mk3 Spit with Overdrive (if that makes any difference) As always, Many thanks to you all in advance. SP Link to comment Share on other sites More sharing options...
johny Posted August 2, 2020 Report Share Posted August 2, 2020 no the diffs for the small chassis cars are all pretty similar but there are 3 seals, front (most likely to fail) and one each side. The first is the easiest to replace and can be done on the car although of course theres normally no easy way to get the oil out first. The side output shaft seals could possibly be done without removing the diff but are more complicated even though each assembly can be removed to a workbench. You need to identify which is leaking and whether you want to replace all three while your at it..... Link to comment Share on other sites More sharing options...
s99sdp Posted August 2, 2020 Author Report Share Posted August 2, 2020 I think it makes sense they replace all of them. They may have been in there since the car was built for all I know so I'd rather go belt and braces and replace all 3. Link to comment Share on other sites More sharing options...
johny Posted August 2, 2020 Report Share Posted August 2, 2020 ok and will the diff be removed to do them? Apparently when changing the side seals theres a good chance the bearings will be damaged in the process so the cost of them may have to be factored in.... I must admit I recently took my diff out but did my front seal only as although the sides are originals they do have a much easier life and werent leaking. Link to comment Share on other sites More sharing options...
s99sdp Posted August 2, 2020 Author Report Share Posted August 2, 2020 1 minute ago, johny said: ok and will the diff be removed to do them? Apparently when changing the side seals theres a good chance the bearings will be damaged in the process so the cost of them may have to be factored in.... I must admit I recently took my diff out but did my front seal only as although the sides are originals they do have a much easier life and werent leaking. no idea, would it be best I find out exactly where the leak is first so that if the side seals don't need changing then we just leave them alone? SP Link to comment Share on other sites More sharing options...
johny Posted August 2, 2020 Report Share Posted August 2, 2020 I think so and if its only the front seal being done professionally they should be able to get the car up in the air and change it in-situ... Link to comment Share on other sites More sharing options...
s99sdp Posted August 2, 2020 Author Report Share Posted August 2, 2020 2 minutes ago, johny said: I think so and if its only the front seal being done professionally they should be able to get the car up in the air and change it in-situ... ok cool, is this all I need to order?......... SP Link to comment Share on other sites More sharing options...
johny Posted August 2, 2020 Report Share Posted August 2, 2020 it looks like DIFFSET1 includes all three seals and rear gasket whereas if youre only doing the front one you will need just items 29 and 34 1 Link to comment Share on other sites More sharing options...
s99sdp Posted August 2, 2020 Author Report Share Posted August 2, 2020 4 minutes ago, johny said: it looks like DIFFSET1 includes all three seals and rear gasket whereas if youre only doing the front one you will need just items 29 and 34 Thanks for that, I'll get on and order it now. 👍 SP Link to comment Share on other sites More sharing options...
s99sdp Posted August 2, 2020 Author Report Share Posted August 2, 2020 Happy days, cheers Johny! Link to comment Share on other sites More sharing options...
johny Posted August 2, 2020 Report Share Posted August 2, 2020 err so now I think youre getting two identical front seals, two identical casing gaskets and two side seals.... Link to comment Share on other sites More sharing options...
thescrapman Posted August 2, 2020 Report Share Posted August 2, 2020 Have you checked your Jigge pin before assuming the seal had gone? 1 Link to comment Share on other sites More sharing options...
s99sdp Posted August 2, 2020 Author Report Share Posted August 2, 2020 (edited) 18 minutes ago, thescrapman said: Have you checked your John gale pin before assuming the seal had gone? I wont be checking anything scrapman. The guy doing the work has quoted me £75 for the parts so I'm just trying to work out if he's buying them in solid gold format. I'll take on board your comment, have a read up what it is, where it is and see if I can check it first. thank you for the heads up. I've just a DM exchange with Johny, I think the best thing to do is get under it and see exactly where the leak is coming from first. At that point I can decide what exactly needs to be bought rather than go for the Hail Mary approach. SP Edited August 2, 2020 by s99sdp adding context Link to comment Share on other sites More sharing options...
thescrapman Posted August 2, 2020 Report Share Posted August 2, 2020 It is on top of one of the rear mounts, just needs to be loose, if stuck the casing pressurises and forces oil out. you can see it removing one of the rear wheels, would need to look at a diff to see which one it is Link to comment Share on other sites More sharing options...
s99sdp Posted August 2, 2020 Author Report Share Posted August 2, 2020 18 minutes ago, thescrapman said: It is on top of one of the rear mounts, just needs to be loose, if stuck the casing pressurises and forces oil out. you can see it removing one of the rear wheels, would need to look at a diff to see which one it is Thank you for that, I'll take a look and see if I can work out what you mean. 👍 SP Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 2, 2020 Report Share Posted August 2, 2020 the breather has a split pin in to reduce the hole and keep it clear ,as said gets clogged with oily gunge and road dirt it is on the n/s just above /rear of the output shaft casting best take the N?S wheel off its easy to see through the chassis /body you cant take the pin out but a degrease /clean up if its looking clogged if you only have a leak from the pinion seal thats all you want to replace ,changing oil seals on the output shafts is not easy output shafts dont have gaskets and youre not splitting the case halves so no gaskets are needed , pete Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 2, 2020 Report Share Posted August 2, 2020 just to add to change a pinion seal its drop the prop undo coupling nut pull coupling off lever out old seal replace new seal refit coupling, torque nut on youres the nut should be a castle nut and split pin , you cant uoset any settings inside the diff , retorque back to where it came from , always turn on to align a split pin not back it off later cars had a nylock nut and collapsible inner spacer these must be refitted to exactly the same position before removal , or you crush the spacer and that can upset the preloads involved so castle nut easy, nyloc be careful you never know whats been changed over the years you dont need to drop the diff for any seal replacements the output shafts with the drive shaft disconnected undo with a hex key through the coupling bolt hols and simply pull out to work on the bench getting their bearings off to change the seal is where you run into a fight Pete Pete Link to comment Share on other sites More sharing options...
s99sdp Posted September 7, 2020 Author Report Share Posted September 7, 2020 Well just to update you, I finally got under the car this weekend and released the pin from 50 years of hurt (gunk, road juice, oil, road kill, ming etc) and its now been freed. We have a spare diff here so luckily I located that one under it's own gunk first and saw how it worked. Basically its a split pin with the ends bent over inside that must rise under pressure. Anyway, that said, I'm sure it will end up the seal that leaking 😆 Thanks again for all the advice, I'm sure we'll replace the seals on the diff at some point but this little tweak is well worth a try to start with. SP Link to comment Share on other sites More sharing options...
johny Posted September 7, 2020 Report Share Posted September 7, 2020 yes its a nice idea and worth a shot. More likely is that its just the front seal that leaks as it has a harder life but fortunately is also the easiest and cheapest to replace🙂 Link to comment Share on other sites More sharing options...
Nick Jones Posted September 16, 2020 Report Share Posted September 16, 2020 Change the front seal first. It’s pretty easy. If the side seals need doing, it’s more effort as the suspension needs partial dismantling to allow the quarter shafts to be withdrawn. Then, once they are out you have the challenge of getting the bearings off to get at the seals. The bearings will almost certainly be damaged in the process as they are very tightly on the shafts, so get some new ones in. Nick Link to comment Share on other sites More sharing options...
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