MG-Cars.info
MG Midget and Sprite Technical front hub bearings!! and brakes BBS discussion at MG-Cars.info
MG-Cars.info
Welcome to our Site for MG, Triumph and Austin-Healey Car Information.
Parts
MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.
|
|
MG Midget and Sprite Technical - front hub bearings!! and brakes
| So, I spent saturday morning fitting a set of skf 40 degree face adjusted bearings for the bearing boys. Fitted them with a 1mm shim to take account of the 2 degree stub axle ratio. Now I have the problem that the brake disc is sitting 1mm outboard of it's correct position which made refitting the outboard pad impossible until I ground off some of the pad backplate. However, the grinding is most likely not straight as I'm getting binding and squealing from both sides. My question is, what is the best way to get the disc back to the correct position? Can I simply insert 1mm washers between the hub and the disc or would this cause other problems? is it better to grind the caliper mounts? The washer solution seems easiest but I'm just a bit concerned about balance etc. I have read through as much of the previous bearing threads but couldn't see the disc issue discussed in any depth. graeme p.s. the skf bearings are solid. No MoT failing wobble at all. |
| graeme jackson |
| Hi Graeme, i used the spacer method, it required 3, one to go behind the bearing to space away from the radius, then one to go between the disk and the hub to move the disk back by the same amount, and one to go behind the seal to move that into the old position. Picture attached of one set... Ive had mine on for 2 years now and no issues... Most important thing i found is to check the dimensions of the inner spacer and the shoulder to shoulder distance in the hub are the same..This, i think is the main reason somepeople have endless bearing issues and some people have none...but it sounds like you are ok on that score if they are solid.. ive got a spare set of spacers at home, someone contacted me to buy them 2 yrs ago but the email trail went dead for some reason.... 
|
| Andy Phillips (frankenfrog) |
| Andy: raking back in my memory, I don't think the spacer and shoulder to shoulder distances should actually be the same. It's the (very) small difference which is there to preload the face adjusted bearings and lock the whole assembly up as a "single" contiguous item. But as the correct face adjusted bearings are as rare as hen's teeth (probably rarer) it's all a bit academic. The issue you raise about spacers is the critical one as fitting a spacer on the inner to clear the radius, calls for a matching pair on the outer and disk to prevent the disk from clashing with the calliper. |
| G Williams |
| Hi Graeme (W), If you get the skf bearing as the other Graeme has then these are face adjusted, there are 3 levels of this according the website. This means that if the outer and inner bearing abutments/spacers are the same then the internal clearances will be to the spec required . I don't think there is a pre load as such. |
| Andy Phillips (frankenfrog) |
| Graeme, YOU BAST#D...I thought you were a friend, no your the face of pure evil Hahaha Im glad you raised this issue... sometime this year im going to 40 contact bearings also I got 1 question I cant find a legitimate answer to...did you use inner spacer or trash it The closet I can find but cant validate is keep the spacer for wire wheels and loose it for solid wheels Any thoughts Prop |
| Prop and the Blackhole Midget |
| Keep it, if it wasn't required then it would have been discontinued at some stage for cost cutting reasons |
| Andy Phillips (frankenfrog) |
| Sorry andy I should have asked... is the spacer tube needed as a spacer between the 2) 40 degree bearings, or does it become extra spare parts Prop |
| Prop and the Blackhole Midget |
| Andy: the difference between the two datums is around 4 thou inch. This is sufficient to preload the bearing races. Face adjusted bearings are designed to carry an axial load of a predetermined value if the alignment of the two faces is offset by a controlled ("face adjusted") amount. If you look at the specs of the originals it indicates the load and the offset. Another much discussed element of all this is the fact that the effect of locking everything up against the spacer, the bearings, the spindle and the hub outer makes it perform structurally as a single unit. This is thought to provide additional strength to the assembly. For this reason, rejecting the spacer is not regarded as a good idea. But for all that, the correct face adjusted bearings with the large radius aren't around any more (apparently). |
| G Williams |
| Where can you get these spacers from? I probably need them on my Frog as it has modern bearings and I have noticed a little bit of play where there wasn't any when I first torqued up the hub nuts. Rob |
| Rob aka MG Moneypit |
| The spacers are inside the hubs... they are apart of the car But are not needed for the taper bearing set up Prop |
| Prop and the Blackhole Midget |
| I got the spacers (the sheet metal ones to space off the bearing from the radius, not the cast iron one that sits between the two bearings) made by myself. I took some measurements, did some drawings and took them to a laser cutting place. They did them within a day, just used sheet metal and cut them out. It cost me about 10 quid. Back in the "oh no not FWB's" thread some enquired at a place in UK and could get them for a similar price. I thought about offering these as a set as a product, but the shipping cost from Thailand is quite a lot... |
| Andy Phillips (frankenfrog) |
| THere are uk companies offering laser cutting, which would suit (just Google it). Alternatively, as Andy says, you could fabricate them yourself. A technical issue to watch out for is that the thin spacer pushes the lip seal further along the shaft and if the spacer is too thick the lip itself could drop off the edge of the shaft. |
| G Williams |
| "But are not needed for the taper bearing set up" Not so Prop. As G Williams pointed out earlier, the spacer performs two roles. One to set the preload on face adjusted bearings, and the other structural, to give additional strength to the spindle. "I have read through as much of the previous bearing threads but couldn't see the disc issue discussed in any depth." Don't know how you missed it graeme, it was discussed at length. :). I wouldn't grind stuff off the pads or the calipers. Hand make the spacers yourself. They don't have to look pretty, you'll never see them once in. Here's my hand made spindle spacer. The disc spacers would take a 'little' more effort, but not much. 
|
| Lawrence Slater |
| If you look at my picture below (or above depending on your settings....) there are three spacers:- The small one to go behind the bearing, The medium one goes behind the oil seal so that it is moved back into the same position on the shaft. The big one obviously fits between the hub and the disc.... |
| Andy Phillips (frankenfrog) |
| Btw graeme. Forgot to ask how much you paid for your skf's from bearing boys? How much including postage? |
| Lawrence Slater |
| Graeme - this was the thread http://www2.mg-cars.org.uk/cgi-bin/gen5?runprog=mgbbs&access=&mode=archiveth&subject=97&subjectar=97&thread=201303171611398748 But be warned..... it goes on and on and..... on and.. |
| G Williams |
| I have a small stock of original NOS RHP bearings if anyone is really stuck. |
| Bob Beaumont |
| Good grief bob I didnt know you worked at the automotive devision of the smithsonian museum Prop |
| Prop and the Blackhole Midget |
| Bob, please can you contact me to talk about a set of bearings |
| dominic clancy |
| Bob, based on what RHP / Orinoco Bearing are charging for those things, if you are sitting on a stock of NOS bearings you might be rich and not know it! Norm |
| Norm Kerr |
| Good grief Bob! You have supplied half of Kent and STILL have stock? |
| G Williams |
| Graham, I know its sad but when my travels take me past a motor factors or motor accessory shop I enquire within!. I have managed to source a couple more sets that way. Very Happy to help a fellow spridget owner out of trouble. My only rule is NO sales to those who just want a spare set though. |
| Bob Beaumont |
| lawrence. £124.13 inc postage For the time being I'm going to put four 1mm washers between the disc and hub (on the bolts) and will see how that works. - the main reason being I can seperate the disc and hub a few mm without taking the hub off the stub axle and potentially ruining the inner bearings if they get stuck (one of the old ones had just about welded itself to the axle and took a fair bit of cutting and hammering to come off). if it's ok then all well and good. If not I'll see about making something up from sheet steel. |
| graeme jackson |
| Graeme: just watch the lip of the seal doesn't drop off the "shelf" into the gap between the bearing and the face of the stub axle. The best reference to all this lot is this one: http://www.mgexp.com/article/mg-midget-wheel-bearings.html The second part (a pdf file) postulates that the bearing not being hard against the step on the stub axle can lead to premature failure of the axle at that point. Whether that is valid is a great discussion point but there must be lots of sprodgets running around taking just that risk. Has anyone evered suffered that sort of failure I wonder? |
| G Williams |
| Graeme: how many bearings for that amount? |
| G Williams |
| G. all 4. |
| graeme jackson |
| That's little cheaper than they were last year from bearing boys then graeme. Last May(2013) it was £66.80 per side (inc vat and delivery). And you shouldn't have to do them again for a very long time. I reckon that's pretty fair value. No need to adjust them ever, and better than tapers for that reason alone in my book. |
| Lawrence Slater |
| graeme. Just noticed the plan(temp) for washers instead of a full spacer. I wouldn't leave it too long with that arrangement. You've greatly reduced the contact surface area between the hub and disc. Could put more strain on the bolts than is good for them. It maybe ok, but as BMC went to the trouble of making sure the mating surfaces were completely flat, and thus in contact all over, I'd put a full spacer in asap. Did you test fit your inner bearing on the spindle for a sliding fit before final assembly? If so you shouldn't have trouble pulling the hub to fit a spacer. |
| Lawrence Slater |
| Andy phillips.. you said.. ive got a spare set of spacers at home, someone contacted me to buy them 2 yrs ago but the email trail went dead for some reason.... Are they still for sale? If so I'd be very interested in purchasing them. Drop me a mail at graeme dot jackson AT lloydsbanking dot com if you're interested. thanks |
| graeme jackson |
| Graeme/Andy: if you could send me the dimensions I can knock out an AutoCad drawing which laser people could use to produce a manufactured set should anyone else need them. |
| Graeme W |
| very easy to design took only a few minutes... here is a picture of the bearing with the two spacers placed on top. small one to space off the radius and bigger one goes between bearing and the seal. inside dia of the small spacer made to clear the root of the radius so it sits flat on the land of the stub shaft. 
|
| Andy Phillips (frankenfrog) |
| Biggest spacer dimensioned to match the face of the disk/hub. photo showing spacer on disk below.... Ive had a look for my original drawing but cant find it, i wont be home for another week or so, but when i do i'll take some dimensions ... 
|
| Andy Phillips (frankenfrog) |
| Andy: I don't have any parts disassembled to check dimensions. |
| Graeme W |
| We know what the bearing and seal dimensions are so can use them to draw up the two small spacers and I'm sure I've got a drawing somewhere of the disk that I downloaded from EBC I think. I'll see if I can sort it out tomorrow |
| Andy Phillips (frankenfrog) |
| OK, managed to get home for the weekend and fished out the spare spacer sets i have. No.1 fits between inside bearing and shaft, this is the one that actually sorts out the mechanical fit issue of the different radii. Inside Dia = 28.9mm outside dia = 34mm No.2 this fits inside the hub behind the oil seal so that the seal is moved back to its correct position (if this spacer was left off the the seal would be 2mm further out than designed and may not seal on the end of the shaft.) inside dia = 45.8 outside dia = 53 No.3 This fits between the brake disk and the hub and moves the disk back centrally WRT the caliper. inside dia 64.9 outside dia 99 with 4 holes dia 13mm on 3.5" PCD I had these made from 2mm thick steel, but i think more common in UK and USA would be 16ths gauge (1.6mm thk) which would be ok. if you get these laser cut then you need to file off the "pips" you can see on the picture, and also use a half round file or dremel and break the sharp corner in the inside of the smallest spacer so that it dosent mark the radius on the shaft in case of it being slightly off spec. installation procedure is:- 1. Fit new bearings into hub, making sure that the internal spacer is exactly the same length as the distance between the shoulders that the bearings go against inside the hub. You may need to get either the spacer or the hub machined. This step is very important as it ensures that the internal clearance of the bearings is maintained. 2. Fit spacer number 2 behind the inside bearing, use plenty of grease to hold it in position. 3. Press in the new oil/grease seal. 4. Fit the large spacer between the disk and the hub. put a light smear of grease on its surfaces just to prevent corrosion and ease dissasembly in the future. 5. Put plenty of grease on the small spacer and position it on the stubshaft. 6.Carefully slide the bearing/hub assembly onto the shaft then tighten up the big nut as normal. |
| Andy Phillips (frankenfrog) |
| Andy, No problem getting 2mm in the UK as metrication was done here years ago, prior to that it was SWG (Standard Wire Gauge). Standard metal thicknesses are 1mm, 1.2mm, 1.5mm, 2mm, 2.5mm, 3mm. The only trouble being some mills seems to be taking the piss regarding the tolerance as I've seen 1.5mm measuring 1.3mm which gets a few more sheet out of a tonne of steel but does sometimes cause issues. |
| David Billington |
| Just sailed through the MOT test. The tester (who has his own MGs) was surprised at how little play there was on the front hubs :-) re the spacers. I got away with a 1mm steel shim (and 1mm washers to move the disc back) . why have you specced them in 2mm steel? wouldn't that push the hub nut too far out so you wouldn't get a split pin through the hole? (with the 1mm shim I was only just able to get a split pin to fit). |
| graeme jackson |
| Good news Graeme, and another success for the spacer method... i cant remember what i originally specified , lot of water under the bridge since then,,, i would have shied away from 1mm as it leaves no room for machining tolerances (and the machining around that area of my shafts didnt look that good...) Maybe 1.2 would be a good compromise..? 2mm worked for me, and i cant remember any issues with the split pin, but mine has been butchered about so mutch that anything is possible. |
| Andy Phillips (frankenfrog) |
This thread was discussed between 02/06/2014 and 17/06/2014
MG Midget and Sprite Technical index
This thread is from the archives. Join the live MG Midget and Sprite Technical BBS now