Hitachi angle grinder - repair or bin?

[mangocrazy]

I was using my Hitachi 115mm/4.5" angle grinder to clean up some earlier cuts in stainless I'd made, when the sound changed, the revs dropped and it started vibrating quite badly. Switched off and on, tried again - same result.

So I started to strip it down as best I could and removed the commutator/motor shaft from the housing and then removed the 'angle' part of the grinder from the main shaft. It quickly became apparent that the bearing on the main motor shaft was rough as a badger's backside and had excessive play. The bearing on the shaft that you fix discs to was fine, spinning freely and smoothly without any play. This seemed fairly typical, as that is by far the easiest of the two main bearings to get at.

I'm now a bit stumped, as I can't see any way to disassemble the part with the faulty bearing. Is this just the way things are in this disposable society of ours, or is it fixable (always assuming I can get hold of the correct bearing)? Viewed in terms of time spent, it probably isn't worthwhile, but if I can get more miles out of what is not a particularly old or heavily used power tool, I'd like to do so. And if cost of repair is sufficiently less than the cost of a new tool, then so much the better.

Does anyone have any pointers or suggestions on how to get at the offending bearing, or do I just hit Google/Amazon/eBay?

 

[Migmac]

I put a new bearing in our “ if you can fix it you can have it grinder” . It’s a Hitachi too, wasn’t difficult and the replacement bearing was cheap. Can’t remember how I did it, I’d have to take it to bits to refresh my memory.

 

[DAPPH]

Use a puller to draw the bearings off.,. Does this help ?

Hitachi Angle Grinder Bearing Replacement • CIMFLOK.COM

Hitachi angle grinder is especially popular among Russian builders. There are two reasons: a high degree of reliability and the absence of fakes. In

cimflok.com

 

[mangocrazy]

Use a puller to draw the bearings off.,. Does this help ?

Hitachi Angle Grinder Bearing Replacement • CIMFLOK.COM

Hitachi angle grinder is especially popular among Russian builders. There are two reasons: a high degree of reliability and the absence of fakes. In

cimflok.com

Unfortunately the bearing being replaced in the video was the 'easy' one. The one I need to replace is in the main body of the grinder, on the main motor shaft, and I can see no way to get at that. I will need to undo an M6/10mm nut holding the gear and bearing onto the main shaft, but don't see how I can get at the nut to undo it. I suspect a special tool may be required.

 

[Agroshield]

Can you post the model number of the grinder? Have you searched for that model number and added the terms 'parts diagram' or 'exploded diagram'? If you can find the diagram, the disassembly process sometimes becomes more obvious.

On this one:

Hitachi / Hikoki G13SE2 Disc Grinder Spare Parts | Miles Tool & Machinery Centre

An exploded diagram and spare parts listing for the Hitachi / Hikoki G13SE2 Disc Grinder

www.mtmc.co.uk

part 11 holds the bearing in the head casting. It is not clear if the shaft complete with gear and M6 nut comes out of the casting or if you need to remove the nut and gear first. Part number 1 looks like it might screw into part number 11 to retain it.

Another place to look is 'Gear show' on YT. He often does full disassembly of Japanese power tools.

 

[sardine]

Replacing bearings in grinders is easy peasy.

Show us a picture of what you've got ?

 

[fizzy]

My Hitachi has been really noisy from day one. Gears don't sound good at all. Wouldn't buy another one. My old Machine Mart special is much nicer.

 

[nickk]

I’ve had all 3 of my 4.5” hitachis breaking down this year,one of which was the bearing at the gearbox end of the armature,I gripped the armature in soft jaws of the vice to slacken the m6 nut holding the bevel gear,then levered it off with 2 pry bars.

 

[mangocrazy]

In the end I took the path of least resistance and took the offending part down to a local power tool repair place. They confirmed nickk's method was the one to use and they got the old bearing off, fitted a new one and charged me a tenner for the job. Bargain...

 

[Bornfree]

My Hitachi has been really noisy from day one. Gears don't sound good at all. Wouldn't buy another one. My old Machine Mart special is much nicer.

Iam very surprised. My 9" Hitachi has lasted 13 years of very heavy work cutting 20mm flat regularly and its still on the original brushes.

 

[fizzy]

Iam very surprised. My 9" Hitachi has lasted 13 years of very heavy work cutting 20mm flat regularly and its still on the original brushes.

My 9" one is great as well.

 

[Puglet1]

Oh,oh.
Reading this has just made me realise exactly how old my hitachi grinder and drill are…… 30+ years.
As an industrial engineer I used them every day for approximately 7yrs. For the past 23yrs, they have been in and out of the garage whenever needed and have never let me down. I’m looking forward to the day that I need to replace the bushes so that I can peer inside one of these fantastic machines.
Sorry to the original post as I’ve been no help whatsoever but as a fellow Hitachi fan I just needed to add comment about these wonderful machines.

 

[bricol]

My Hitachi has been really noisy from day one. Gears don't sound good at all. Wouldn't buy another one. My old Machine Mart special is much nicer.

Open the gear case up - clean what's left in there masquerading as lubricant and replace - don't pack it though. On one of mine, there was a loose nut holding a gear too. Tightened, new grease - lovely. For a day or two But at least I knew there was new grease moving around in there when I got it nicely warm.

 

[sardine]

I got hold of the entire parts stock from a closed down tool hire company and a few box fulls of well abused Hitachi grinders in bits, the gears on them were not worn at all after years of use.

 

[mangocrazy]

Yes the gears on this (inexpensive) grinder are steel and in very good shape, so it's worth fixing.