Compressor in 8455 Backhoe

[kristl]

Hi guys, I have a question for you:

Has any of you modified or seen a 8455 backhoe with a two pump compressor and battery onboard?

I managed to get two pumps inside by removing the differential and installed an M motor instead of fake engine, but I think it could be done better since my "by product" was decreased steering lock which already isn't great . One pump is quite easy to install (but barely sufficient, since the thing has 10 pneumatic rams), but I would really love to see a well braced two pump design without compromising the look of the machine. I found some videos on youtube but those modifications where either just adding an airtank to manual pumps or were nowhere as elegant (parts sticking outside of the vehicle for instance) as I would like to see it . I know it's quite an old set and there isn't much chance that people here are still occupied by it (especially with the Unimog and all the newer sets) but maybe somebody found a solution once and would be prepared to share it.

Edited October 10, 2011 by kristl

[davidmull]

I often wondered this too,it's really missing a compressor in my eyes,would make the set more interesting,

[trekman]

I often wondered this too,it's really missing a compressor in my eyes,would make the set more interesting,

We worked at this recently and we (my son & I) were able to fit a two pump compressor into the cab. We were able pull the existing pumps out and install a 9v geared motor and the minipumps. we had to move the steering axle a bit, but there was room for the workings. We normally power static models from a 220v transformer, so we did not have to worry about a battery box. We were also able to refit a larger pump (to look like an exhaust) into the air supply when the transformer was disconnected.

I does make some difference to the performance!

What I was amazed about in this model was how TLG were able to create a full 180 degree back actor swing from ONE pneumatic ram and a 1/2 stud offset. The design work in this model surely makes it a classic.

[davidmull]

We worked at this recently and we (my son & I) were able to fit a two pump compressor into the cab. We were able pull the existing pumps out and install a 9v geared motor and the minipumps. we had to move the steering axle a bit, but there was room for the workings. We normally power static models from a 220v transformer, so we did not have to worry about a battery box. We were also able to refit a larger pump (to look like an exhaust) into the air supply when the transformer was disconnected.

I does make some difference to the performance!

What I was amazed about in this model was how TLG were able to create a full 180 degree back actor swing from ONE pneumatic ram and a 1/2 stud offset. The design work in this model surely makes it a classic.

I must buy this set so ;)

What I could do then is run it off my 8110 pump easy ;)

[Alasdair Ryan]

I would like to have a go my self but it is in bits at the moment.

I just checked the instructions and you should be able to fit a compressor were the fake engine is,removing the pumps should leave you with enough space for the battery box you may need a valve as well but fitting this should not be to hard.

Edited October 11, 2011 by Alasdair Ryan

[kristl]

I would like to have a go my self but it is in bits at the moment.

I just checked the instructions and you should be able to fit a compressor were the fake engine is,removing the pumps should leave you with enough space for the battery box you may need a valve as well but fitting this should not be to hard.

You're right about the batterry box, it fits nicely where the manual pumps used to be, but you're over estimating the available space in the front where the fake engine is. It's only three studs wide (even if you try to squeze the pump in vertically, the tubes coming from the nozzle would obstruct the front end loaders motion when going up or down) so the only thing that fits there is an airtank or M motor. So in my opinion the only place where you can put the pumps is where the differential and the geartrain for the motor used to be. But maybe you're right and I am not thinking out of the box enough... It would be great if you would take the time and try out your theory, that is if you can put your current projects aside for a short while...

@trekman:

You wouldn't have a photo of your solution laying around would you?

P.S. I did try gearing up the single pump compressor from 1:1 to 1:1.667 and it does help to bring some extra air into the system. I'll take a photo of my solution during the day when the lighting is better.

Edited October 11, 2011 by kristl

[trekman]

You're right about the batterry box, it fits nicely where the manual pumps used to be, but you're over estimating the available space in the front where the fake engine is. It's only three studs wide (even if you try to squeze the pump in vertically, the tubes coming from the nozzle would obstruct the front end loaders motion when going up or down) so the only thing that fits there is an airtank or M motor. So in my opinion the only place where you can put the pumps is where the differential and the geartrain for the motor used to be. But maybe you're right and I am not thinking out of the box enough... It would be great if you would take the time and try out your theory, that is if you can put your current projects aside for a short while...

@trekman:

You wouldn't have a photo of your solution laying around would you?

P.S. I did try gearing up the single pump compressor from 1:1 to 1:1.667 and it does help to bring some extra air into the system. I'll take a photo of my solution during the day when the lighting is better.

I have stuck this photo in for now. This was the same compressor which was in the cab of the 8455. note that you will need to use something like those cams to create a 1/2 stud spacing, utilising the full stroke of the minipump. We may have rebuilt the grey frame on later, as I think we needed to have the external dimensions a bit tighter.

I do not believe you would have the room needed for the pumps to rotate under the bonnet of the backhoe.

[Alasdair Ryan]

I have built it up,now i need to fit the compressor and the battery box in it,should not take me too long.

[timslegos]

I have built it up,now i need to fit the compressor and the battery box in it,should not take me too long.

Post some pictures!!!

tim

[Alasdair Ryan]

Ok It still needs work done to get it working (i think i wired it up wrong) . It has 2 small pumps in it (stepped),i know it is a bit week and would be better if you mount the pumps somewere else but this is fine for me.

[kristl]

Ok It still needs work done to get it working (i think i wired it up wrong) . It has 2 small pumps in it (stepped),i know it is a bit week and would be better if you mount the pumps somewere else but this is fine for me.

I'm very intrigued by your design and it looks quite promising. Any chance you can take better photos or make an ldd file?

[Alasdair Ryan]

Its not very strong so i will need to go back to it i am on holiday to Perth (scotland ) for just less than a week so you may need to wait a bit for progress.

[Alasdair Ryan]

Well i have came up with a good compressor although a little slow for the 8455 backhoe ,i have added free instructions so you can build it your self,you will need to make a few changes to the boom mounting.

Download Instructions

A wee video.

[kristl]

Well i have came up with a good compressor although a little slow for the 8455 backhoe ,i have added free instructions so you can build it your self,you will need to make a few changes to the boom mounting.

Download Instructions

A wee video.

Yeah, it is kind of slow for a two pump compressor, my present solution moves pistons a lot faster:

It fits right where the differential should be and the motor serves as a bit of counterweight instead of the fake piston engine.

LXF file download: File

Edited October 17, 2011 by kristl

[Alasdair Ryan]

Your one is better then ,hay ho i can take my backhoe apart again.

[davidmull]

I really want to buy 8455 now,new one of course :) is it really as good a set as everyone says?

[DLuders]

@ davidmull: There are 19 reviews of the 8455 Backhoe on this Brickset website.

[Jim]

I really want to buy 8455 now,new one of course :) is it really as good a set as everyone says?

How much are you willing to spend on this model? And do you want to have it for display or to build and reuse the parts?

[davidmull]

How much are you willing to spend on this model? And do you want to have it for display or to build and reuse the parts?

I want it to build and display ted why?

[Jim]

I want it to build and display ted why?

First of all, I don't own the set, so I am not really the one to judge...

...however, partwise it does seem nothing more than a large collection of pneumatic parts. So if you want to build it once and canabalize it for parts, I guess you shouldn't pay top dollar for a new set. You can get the pneumatic parts via Bricklink quite easily and most of the other parts are not that special.

On the other hand, if you want to add this to your collection and display it, paying extra for an entirely new and complete set is understandable. I would do the same.

Hence my question

Btw I haven't read the reviews on BS, so this only reflects my feeling from looking at the pictures. Okay, maybe I should read the reviews too

Edited October 18, 2011 by Gekke Ted

[davidmull]

I just red the reviews and there all good,apparently this is in the top technic sets of all time :)

[timslegos]

Yes i would agree it is one of the best sets of all time. I got the set when i was probably 8 and it took 2 times to build the beast before it worked properly. This set is loaded with pneumatics! It is a great resource for cylinders and hoses and pumps. Overall it is a fantastic set and it is well worth the money!

tim

[davidmull]

Can anyone tell me why there is a black or a yellow box version of this set? Also why does it say 11-99 on the yellow box,there has to be a story to this one! Which box is more sought after as well?

[Jim]

I just red the reviews and there all good,apparently this is in the top technic sets of all time :)

So it seems!

I think this set is considered to be one of the best, is because everything can be controlled (pneumatically). Even the stamps.

Well, the choice is simple my friend.....go get it!

[davidmull]

Can anyone tell me why there is a black or a yellow box version of this set? Also why does it say 11-99 on the yellow box,there has to be a story to this one! Which box is more sought after as well?

Can anyone answer this for me?