Anyone have tips for a hewland mk8 ?

[ace rimmer]

I’m getting ready to put a mk8 together and I was hoping someone would have some tips for me. All bearings have been cleaned and checked, all treads have been chased ,all gears and shafts are as clean as can be . I’ve cleaned and checked all parts . I’ve got new seals and new cross shaft bushing and all new nuts,bolts and studs. In other words I’m ready to rock an roll . if you have some tips then please share .
thank you much

[Brian]

How far apart did you disassemble it? Did you take the bearing carrier completely apart? Did you take the shift forks off? Did you take the pinion out?

Brian

[ace rimmer]

it's all the way down . bare case and forks are off ,pinions out. the diff is still together with bearings still on it . it's a box of parts right now. what i'm looking for are the learned tips .
thanks for looking

[kea]

If you don't own the Jigs (and a bit of experiance helps), then Good Luck!
It can be done, but to do it correctly, it will be a slow, trial and error process.

[Brian]

If you haven't done one before, send it to a pro shop and get them to do it. That's the honest tip. building it from where you are now takes a fair amount of skill, experience and at least a thousand dollars worth of jigs and special set-up tools. Not to say you can't do it, and not to say you might not even be able to do it right. but honestly, if you need to ask to tips on how to do it, that's the first clue that you can't do it.

I recently costed out acquiring the tools to install a ring and pinion, and they are more expensive than getting it done by a pro shop. So you'd save money the second time, I guess, considering your time is free. It's possible to build up a bearing carrier without a jig, but unless you know exactly what to do, it's very hard to get it right. Very easy to do wrong, I can say from experience, but hard to do right with no tools.

If you want to try, the instructions are in the manual that's available for free download from the Hewland web site. The hardest part is shimming the pinion. Without the tool, there is literally no way to know if you did it right. It is possible to build the bearing carrier, align and shim the forks and set the gear end-float without the fork jig, having done it several times, but I knew how to do it before I started so I knew what I was trying to achieve. Have fun, good luck!

Edit: Telling the truth, it is possible to shim a pinion and ring gear properly with a dial indicator to measure play and that yellow indicating grease to show the contact pattern, but doing it that way is getting a little extreme. That's supposed to be for checking that you did it right.

Brian

[ace rimmer]

[FONT=Verdana]I’ve rebuilt vw Trans and many ford rears before, I do have a old vw trans case that's been opened up for setting up vw’s, I’ve also been pulling wrenches for twenty five years or I did [/FONT]

[Brian]

I thought of some tips for you. Pretty basic stuff, but may help, so...

Install the pinion, and use the same shims as it had when it came out. Install the RH side plate, drop the diff in and start to work out the pinion height and the gear float using the indicator paste method (I did that about 25 years ago with a Chev diff, believe it or not...). Then get the diff preload right. The Hewland manual has the method for checking the gear clearance with a dial indicator on the nut end of the pinion. Doing this without the special checking bearings (which are ground down so you can pop them in and out without heating the transmission case) is a PITA, but is possible.

Before you install the diff for the last time remember to install the input shaft and the coupler, then don't let the input shaft slide forward or the coupler will fall off.

Build up the bearing carrier following the diagram in the manual and loose set the shift forks. Leave the shift fork detent springs looseish so that you can move the shift forks kinda easy. Put the bearing carrier in a vice so that the gears will sit vertically. Take an old pinion (or do this before you install your pinion) and install it in the bearing carrier with all of the gears, spacers, dog rings, etc, and a .008 thou. extra shim below top gear (to simulate top gear end float). do up the pinion nut to take out all play and make the pinion stand up straight. Shim the shift forks so that the dog rings are centered between their gears and they float inside of the forks radially. Do up the shift fork nuts using new metallic self-locking nuts and no bendy locking washers. Do this so that the shift finger end of the shift rods are in the right position - I use feeler gauges and adjustable wrenches to get them in the right spot, and frankly curse a lot. This part is a PITA.

At this point, if you did it right, the shift forks are set right. Now adjust the detent ball/spring allen bolts until you need about 20 lbs of force to shift each gear, pressing on the end of the shift rod.

Now assemble the bearing carrier, with a complete pinion hub stack (take out the temporary end-float shim that you used to shim the forks, and the only gear you actually need at this stage is top gear, you can leave the other ones off)) into the box with no layshaft, bolt it together and get at least some torque on the big pinion nut to make sure the gear stack has some pre-load. Now stick your finger in the layshaft hole and spin the top gear, and try to feel for how much end float it has. The Hewland manual has the spec, and you set the top gear end float by shimming the gear stack directly under the pinion bearing.

Now assemble the gearbox with all the gears and the layshaft. Remember that with no crankshaft to keep the input shaft from pushing forward you will have to work out a way to hold the input shaft in exactly the right position so that it doesn't push forward and the coupler falls off when you stick the layshaft in (this makes sense after you've done it wrong and you have to take the diff out to put the coupler back on). See if it shifts. See if it shifts into two drive gears at once (first and third, second and fourth of a four speed). It shouldn't do that. See if it can shift into reverse and third at the same time, locking the gearbox up - it should do that.

Take it apart again and put it together again with black silicone seal (or other goop of your choice) on the mating faces of the bearing carrier to the main housing. Do up all of the nuts to squeeze the goop. Put the gearbox in reverse and third and torque the big nuts to the required spec from the manual. Now look and see if the cotter pin holes line up. If they are close, add torque to get them to line up, never take torque away. If they aren't close, take the nut off and cut a few thou. off in your lathe so that when you torque it properly the holes line up. Now, and forever more, you can just do up the nuts so the holes line up and the torque is correct. Don't forget to put the input shaft retaining bolt in before you put in the cotter pins.

If you know how to build gearboxes, this will get it done for you.

Brian

[Doug Punches]

[FONT=Verdana]I’ve rebuilt vw Trans and many ford rears before, I do have a old vw trans case that's been opened up for setting up vw’s, I’ve also been pulling wrenches for twenty five years or I did [/FONT]

Hi, I work at Taylor Race Engineering and we can blueprint your box for you. We have been Servicing these boxes for over 30-years. I understand that you are a mechanic and may very well be qualified to build the box; However, without the proper set-up tools, it will be difficult to build the box properly. You will need a Pinion Depth Tool - $279, Differential Set-up Bearings - $90, A Shift Fork Jig - $650 and possibly a Pinion Nut Wrench - $128 = $1147 Tools only. We charge $1199 to Blueprint a MK-8 and the work will be done by Technicians that work on these boxes everyday.

Am I trying to earn your business? Yes! I'm also trying to save you a lot of grief and ultimately money. I've seen a lot of people actually spend more money on a gearbox that didn't work properly than a Professional Blueprint.

[ace rimmer]

Thanks Brian for the info.
I do have one question that I cant find a answer to. I’ve never used synthetic gear oil before, I’ve always used assembly lube when putting a gear box together . should I use a synthetic assembly lube or just use gear oil . I know some synthetic oils can foam when mixed with a non synthetic assembly lube.

[Brian]

I assemble the box essentially dry, just a light oil if anything inside of the bearing carrier shaft tunnels - I keep 20W50 in my bench oil can. I personally use no assembly lube, if you mean a thick grease type lube. The roller bearings inside of the gears should be wet with whatever gear oil you plan to use to run the box. if you use Redline, it's a very adherant gear oil that will stay where you put it. But there is no need to go overboard, everything is splash lubed. The ring and pinion gets lubed the first time it goes around. My practice mayy vary from that of people who do this for a living, but I really don't think pre-lube is very critical in this box.

Edit - when you fill the box before running it (after it's in the car) if it has two fill plugs on top you can put half the fluid in each, that gives the distribution of fluid inside the box a head start. If it only has the fill plug on the diff section, pour it all in there and if you have time let it sit overnight so that some of the fluid migrates to the gear part of the box

Brian

[SCOTTY81]

Ace,

Brian is correct...a squirt can of oil will do the trick.
A real good coating on the needle bearings that the gears ride on .
Also get under the spider and side gears of the diff real good.
Lay some oil down on all the teeth of the gears as well as the R&P and all the bearings

Too much oil will not hurt at all.
If you are in a high humidity environment spray the gearstack down with WD40 after everything is stacked up in the bearing carrier.

Scotty
Taylor Race Engineering
Technical support and sales.
scotty@taylor-race.com

[Charles Warner]

Before you blast down this road . . . . re-read the responses you've gotten . . . and consider again the recommendations to send it to a pro shop (TRE are the best but there are others) for rebuild. I realize you feel you have the experience . . . and you might. However, consider that your desire to save money could be a case of false economy. Remember the old Fram adds? "Pay me now . . . or pay me later." And,I guarantee, if it's a matter of "pay me later" the costs will be much higher.

Send it out and be done with it.

[Brian]

Before you blast down this road . . . . re-read the responses you've gotten . . . and consider again the recommendations to send it to a pro shop (TRE are the best but there are others) for rebuild. I realize you feel you have the experience . . . and you might. However, consider that your desire to save money could be a case of false economy. Remember the old Fram adds? "Pay me now . . . or pay me later." And,I guarantee, if it's a matter of "pay me later" the costs will be much higher.

Send it out and be done with it.

Some people like to do things themselves. I can sympathize. I do virtually everthing on my cars myself, because that is the larger part of the enjoyment of the hobby for me. Thinking on it, about the only things I haven't done on my cars myself is install and cut valves seats in heads, anything that requires a foundry - and - wait for it - install a ring and pinion in a Hewland!

I guess I never sleeved a block either, but I also haven't paid to have anyone else sleeve a block so it doesn't count...

[Charles Warner]

Some people like to do things themselves. I can sympathize. I do virtually everthing on my cars myself, because that is the larger part of the enjoyment of the hobby for me. Thinking on it, about the only things I haven't done on my cars myself is install and cut valves seats in heads, anything that requires a foundry - and - wait for it - install a ring and pinion in a Hewland!

I guess I never sleeved a block either, but I also haven't paid to have anyone else sleeve a block so it doesn't count...

Brian,

I agree with the concept of enjoying the tinkering and the sense of accomplishment when a new task is performed. I also remember the frustration and costs when I screwed up the task to the point of costing not only time but money, at times making me miss an event. IMO, given the initial request, I surmise the gent has little understanding of Beasts Hewland. It would be wise (again IMO) to start with a known item in proper condition. I have rarely seen used gearboxes that were not in need of some real care by the pros. As was pointed out, the tooling required to do a proper job is extensive, costing more than the blueprinting. Obviously, mileages vary.

[ace rimmer]

Well I’m never going to do that again. it’s not that hard to do and I have a old jig from my vw days but, you need five hands with thin fingers and well I don’t hands like that .i had to try and next time I’ll let someone else do it .