TB48 Brake Booster Upgrade to GQ 2.8TD

[PeeBee]

The Willwood brakes are getting fitted today. The fine print states if the brakes feel 'spongey' after the upgrade, and larger capacity master cylinder may be required (something to do with the change in bias flow to the rears and volumetric capacity?). The recommendation is upgrading from the 2 bolt master cylinder and brake booster in the GQ to the 4 bolt master cylinder and booster out of the 4.8. ( Brunswick don't change the brake booster or master cylinder when they do the upgrade.)

Has anyone done this upgrade, is it a straight swap? Is the 4.8 unit physically larger in size? Where can i source a service kit for the booster as the units are only avail s/h from P.A.P.

The kit includes braided lines as well, however these are already fitted.

[mudski]

The GU Boosters, clutch and brake are non servicable. But, back in the day places like ABS used to repair brake and clutch boosters. I used to do this all the time for work. But that was 20 years ago. Pretty sure there would still be a few places where you could take a booster for repair. Just gotta find them.
As for physical size. I am not sure.

[PeeBee]

Thanks Mark, was going to throw a 'kit' thru the s/h booster as a precaution. Guys didn't start on my setup today, maybe should not have given them a couple of days! Anyway will see how it pulls up and then decide.

[Cremulator]

I've been looking at this Hydraulic Brake Booster Upgrade from Mark's 4WD and considering this upgrade with better pads, rotors and braided brake lines (with factory GU III TD42 calipers/rotor size).
https://www.marks4wd.com/mfk20130.html
Not sure if this would fit your GQ though.

[PeeBee]

I've been looking at this Hydraulic Brake Booster Upgrade from Mark's 4WD and considering this upgrade with better pads, rotors and braided brake lines (with factory GU III TD42 calipers/rotor size).
https://www.marks4wd.com/mfk20130.html
Not sure if this would fit your GQ though.
This ended up being too custom for what I wanted. Marks don't do a GQ kit anymore or maybe never did. poindexter has this fitted to his gu ute. It's a lot simpler than the route I have taken and from a YouTube clip I saw it pulled up the patrol 40% shorter, so a worthwhile upgrade for sure

[Gutsquisher Media]

This ended up being too custom for what I wanted. Marks don't do a GQ kit anymore or maybe never did. poindexter has this fitted to his gu ute. It's a lot simpler than the route I have taken and from a YouTube clip I saw it pulled up the patrol 40% shorter, so a worthwhile upgrade for sure

Strange, Marks still have the Hydro Brake Booster listed on their web page for the GQ https://www.marks4wd.com/vehicles/nissan/gq

[PeeBee]

Strange, Marks still have the Hydro Brake Booster listed on their web page for the GQ https://www.marks4wd.com/vehicles/nissan/gq

Give them a call. They don't have a kit. They can make one up but you need to leave the vehicle with them so they can get the hoses and fittings correct. I suppose they have to draw a line as to what they carry, and with so many people building custom rigs, maybe the bulk market isn't there. As as example, you can still buy a portal Kit from them for a GQ, but they will resist selling it as it has not undergone second stage manufacturing testing and verification. The GU diff housings are the platform, and we all know they fit the GQ. I was unable to find a VASS engineer in Vic who would take on this testing when I looked at it 5 yrs ago, and shortly afterwards Marks dropped the GQ listing.

[PeeBee]

OK, kit fitted and clears the rims, however the mechanic says it needs a fair bit of force to get the barge to stop, he was expecting it would be spongy if anything - thinking it may need a larger booster, like the 4.8? The vac assist is working, just not clamping as hard as i/he would have expected. Thoughts? Might have to head to PAP tomorrow for the 4.8 set-up.

[Hodge]

OK, kit fitted and clears the rims, however the mechanic says it needs a fair bit of force to get the barge to stop, he was expecting it would be spongy if anything - thinking it may need a larger booster, like the 4.8? The vac assist is working, just not clamping as hard as i/he would have expected. Thoughts? Might have to head to PAP tomorrow for the 4.8 set-up.PeeBee. 4.8 Brake stuff is treated like gold ingots at Patrolapart. You'll be paying through your nose for it. It's very sought after gear. I believe they only have refurbished units ...

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[nissannewby]

Maybe it hasn't been bled properly? Easy to check if the vac is working. Take to vacuum line off and test. Will know pretty quick if there is a change.

A larger master cylinder will allow more line pressure for less effort and the larger booster assists with the increase master volume. It's pretty easy to test brake pressure to see if your at the limits of the gq master. There are also various size masters in the GQ.

GQ brakes are shit when they are at factory tare let alone grossly overweight.

[PeeBee]

Maybe it hasn't been bled properly? Easy to check if the vac is working. Take to vacuum line off and test. Will know pretty quick if there is a change.

A larger master cylinder will allow more line pressure for less effort and the larger booster assists with the increase master volume. It's pretty easy to test brake pressure to see if your at the limits of the gq master. There are also various size masters in the GQ.

GQ brakes are shit when they are at factory tare let alone grossly overweight.

Thanks Matt, I have a gauge on the vac reservoir, and its pulling down hard. I have not driven it myself, however the mechanic I use and trust is not that happy either. I will make some enquiries with 'The rod shop' in the morning and see what they can offer. their initial thoughts were towards the 4.8 Booster and master cylinder. my issue is the booster is not serviceable as such, and only avail s/h unless I shell out another grand for a new one , which i will do if certain it will deliver the goods. the master cylinder is a slightly larger bore on the 4.8 also. the master cylinder is a brand new factory new unit but for the 2.8 TD engine.

Appreciate the help Matt. this is the final piece of the puzzle on the build so want to do it correctly.

[PeeBee]

PeeBee. 4.8 Brake stuff is treated like gold ingots at Patrolapart. You'll be paying through your nose for it. It's very sought after gear. I believe they only have refurbished units ...

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Hodgey, they only sell new master cylinders and s/h booster units, the new ones are pretty dear, but if its what is needed to complete the picture I will buy. What i don't want is to find its not going to deliver. I have gone from 6 pistons to 20 so expect there to be a net increase in clamping force. I am wondering if the new piston seals aare still tight or unlubricated? Clutching at straws, will see what tomorrow brings. thanks for the post.

[nissannewby]

Plenty of new ones available ex Dubai. But still expensive over there at $965 aud plus freight.

46 Brake Boosters in stock to suit the 4.8.

[PeeBee]

Plenty of new ones available ex Dubai. But still expensive over there at $965 aud plus freight.

46 Brake Boosters in stock to suit the 4.8.

Thanks Matt, I will see what tomorrow brings. I might take it to a brake specialist at last resort to check the actual pressure. Purchasing new isn't a problem as long as it is the correct diagnosis.

[PeeBee]

Righto, picked the vehicle up after the pads were removed this morning and de-glazed. The bedding in process for the pads is quite brutal in some regards and I took the vehicle out, following the Willwood Brake bed in procedure where possible. the brakes certainly improved, not quite at 'thru the windscreen' stuff yet, but I ran out of time, so will give them a pounding when I return after next roster. As they are now, they would pull up at 60kmhr in half the distance on patchy dry/wet road - bit hard to lean hard into them as the mud pattern simply locks up. The balance from front to back feels good also. I will see how this progresses, and if required move to the TB48 set-up. Pedal is firm and good feel also.
Only moan is the pads are misaligned by about 2mm on the outer circumference, and after a 30klm trip there was a 0.25-0.5mm brake pad lip. Waiting for a comment from The Rod Shop now.

Rod Shop say the offset is normal for the rears, but not the fronts, so something else to look at. They don't see it as a major, but does not make sense to have a portion of the pad not doing anything. They are recommending the 4.8TB master and booster so will see how I travel with the next roster break, but could be on the cards.

[PeeBee]

8363883639

[PeeBee]

OK, ordered the s/h TB48 booster and new TB48 master cylinder from PAP this morning. Spoke with 'Shorty', very helpful. They are sending it by courier to get around the 5klm rule. Next job is to find the master cylinder and booster as its covered in the usual PeeBee rats-nest of cables.

[BrazilianY60]

Thanks Matt, I have a gauge on the vac reservoir, and its pulling down hard.

Hi PeeBee.
Any chance you can post a picture of this vac gauge? Is it under the bonnet or in-cab?

[PeeBee]

Hi PeeBee.
Any chance you can post a picture of this vac gauge? Is it under the bonnet or in-cab?

83709

Here you go. It came integral with the larger reservoir. Sits around -23-24 from memory

[BrazilianY60]

Not even close to what I was imagining, just for that supercharger nose cone there, LOL. I thought you were talking about that small OEM reservoir.

[PeeBee]

Not even close to what I was imagining, just for that supercharger nose cone there, LOL. I thought you were talking about that small OEM reservoir.

The original nissan one would be adequate I am sure, its just a difficult shape to mount away fro the original position. The gauge could be tee'd into a vac line and located in the cabin if required. I have enough going on inside my patrol, so dont need another gauge sitting there.

[PeeBee]

OK, decided to make a start on the swap out today - what a mission. Took 2 hours to clear the cables under the bonnet out of the way so i could find the booster and master cylinder. Then stuck my head under the dash to access the 4 firewall bolts and pedal assy - Oh my god, what a cluster. the extra fuse blocks have to come out, so all those damn wires disconnected and then I will have access to the pedal. Familiar ache in the neck and lower back coming around again, any wonder the garage mechanic I use said Get F....d, you can do that. Back into it tomorrow, hope to have the assy swapped out then another day to reconnect everything.

[PeeBee]

After stewing about actually starting, he is what 6 hrs of neck twisting labour delivers - Right back at the start of my wiring tidy up. Sent the s/h PAP TB48 booster away for a birthday. mudski kindly supplied a recommendation, apparently there are very few places in Vic that actually rebuild brake boosters! Anyway, another $350 into the pot, but at least I know it will be 100%.8375683757

[mudski]

Sorry mate I didn't have time to talk today. Its absolutely chaos at work lately. It takes me 3 hours to eat lunch (if I get to actually get it out to eat) which would take 5 minutes.

[PeeBee]

Sorry mate I didn't have time to talk today. Its absolutely chaos at work lately. It takes me 3 hours to eat lunch (if I get to actually get it out to eat) which would take 5 minutes.

No problems. Took the unit down there, the lady was really friendly, will be back to me on thursday morning with a quote then back in hand about a week from now. Better to spend the money on a refurb than have it fail and have to go thru the same 'de-wiring activity' I have just gone thru. Thanks for the swift text return though Mark.

[mudski]

I hope it all turns out well for you mate.

[PeeBee]

Well, bit of an update, good news for a change. I was told the TB48 brake booster was a non serviceable item and a throw away. Seems there are kits avail to get the booster overhauled. By who, I don't know, seems a closely guarded secret to some degree, but either way, if you have a TB48 and need to replace parts in the booster its possible. The new price of a booster is circa $1000, but a service activity is under $350 - good to know.

[mudski]

Well, bit of an update, good news for a change. I was told the TB48 brake booster was a non serviceable item and a throw away. Seems there are kits avail to get the booster overhauled. By who, I don't know, seems a closely guarded secret to some degree, but either way, if you have a TB48 and need to replace parts in the booster its possible. The new price of a booster is circa $1000, but a service activity is under $350 - good to know.

Did they say anything was wrong with the booster Phil? It will be interesting to see the difference with the TB48 booster and master cylinder.

[PeeBee]

Did they say anything was wrong with the booster Phil? It will be interesting to see the difference with the TB48 booster and master cylinder.

I have asked them for feedback. I dont know the history of the booster unit as S/H from PAP. Needless to say it has a 3 month warranty and they check its function before selling it. The master cylinder has another 1.3mm larger diameter so it can exert greater pressure into the system, or thats the theory. Master is a new unit.

[PeeBee]

Picked up the refurbished TB48 brake booster, shiny and black, new boots and whatever. The requested condition report and returned parts never happened. The only grunt was to the effect, ' oh ya know, things get old and perish, thats about it', so none the wiser on the condition of the original parts. Protex is the mob in Melb, cost $340 incl GST. Money in the bank I reckon, no doubts. Just got to fit it now, which might get done Sunday.

[PeeBee]

TB48 booster and master installed, bit of a squeeze, but fits. Tidy up of wiring on final leg I think.
839698397083971
Bleed the brakes tomorrow and see it pulls up.

[PeeBee]

Almost done, just need to trouble shoot the diff locks, UHF radio and fuel computer as all dead - no doubt a simple wire on the wrong terminal. Also truck won't turn off via the turbo timer, intermittent fault as it was earlier in the day, no doubt a terminal issue again. Happy to hear the beast start up though after 4 weeks off the road. Going to start the gravity bleed of the brakes tomorrow so i can at least get it to the mechanic for him to bleed them properly and do a final look over the job.

[PeeBee]

Doing a preliminary gravity bleed of the brakes tomorrow. Staring at pass rear, then drv rear, pass front and drv front, does the rear proportional valve need to be individually bled or will it clear via the two rear bleeds?

[nissannewby]

Yes bleed it. Due to its operation and position it is best practice to bleed.

[PeeBee]

So that was an interesting exercise. I read and heard it should take 1 hr for the first wheel, 45 for the second then quicker for the final two. Well, 3.5hrs for pass rear, 1.5hrs for drv rear, 15 minutes for pass front and 5 minutes for drv front, nice and hard pedal. Still taking it down to the mechanic to have him re-bleed/check the job. I did get tripped up at first as the Willwoods have four bleed nipples per caliper, and I only saw the top outer nipple at first and cottoned onto the second top nipple after an hour. Anyway, bled both sides and all good.84014

[Rossco]

Nice one. . . Keen to see how they go tomorrow . .[emoji106]

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[PeeBee]

Nice one. . . Keen to see how they go tomorrow . .[emoji106]

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Thanks Rossco, as I suspected the bubbles cleared 10 mins after speaking with you, should have just persevered I guess, however they simply didn't seem to want to stop, then they did. Need to ring the mechanic to see when he has a first up morning slot this week.

[PeeBee]

Trip down to mechanics for a brake bleed check, tiny bit out of pass rear, which did make a difference. Brakes are noticeably better, certainly have a better feel about them. Popped a photo in of 'exceptional flex' for some eye candy to all those chasing something like I have achieved - this was just before it started to teeter84023 on the edge of falling off the jack!

[Rossco]

She's look'n good, glad brakes are better you'd hope so [emoji106][emoji106]

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[mudski]

Nice. Good to see its worked out for you.

[PeeBee]

Thanks mudski, Rossco, yes they are better, lot of bucks though. I would hate to drive a hydro boost unit and find it was better though! All up a shade over 6k. Happy I had the booster overhauled and did the final bleed check with the mechanic, total peace of mind. Anyway, thats it, no more room for anything, dont need anything else, only want to sort out the crap car radio reception when up the bush and the degraded HF radio reception which I think may be from electronic interference inside the vehicle.

MudRunnerTD has left 6 messages on my phone wanting to know how he can achieve the same flex on his white brute - might just hold off on calling him a little bit longer!!!

[MudRunnerTD]

Thanks mudski, Rossco, yes they are better, lot of bucks though. I would hate to drive a hydro boost unit and find it was better though! All up a shade over 6k. Happy I had the booster overhauled and did the final bleed check with the mechanic, total peace of mind. Anyway, thats it, no more room for anything, dont need anything else, only want to sort out the crap car radio reception when up the bush and the degraded HF radio reception which I think may be from electronic interference inside the vehicle.

MudRunnerTD has left 6 messages on my phone wanting to know how he can achieve the same flex on his white brute - might just hold off on calling him a little bit longer!!!Bhahahahaha. You win.

I can't wait to see this thing mate!!! You have done a huge job on it. A credit to you.

Never shall an enthusiast say.... It's Finished.....

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[Rossco]

Awesome mate, time to enjoy it I reckon [emoji106][emoji106][emoji106]

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[Winnie]

Hahahaha bloody funny.....
In regards to the radio reception, don't bugger around with it and just buy a Spotify subscription instead.

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[PeeBee]

Hahahaha bloody funny.....
In regards to the radio reception, don't bugger around with it and just buy a Spotify subscription instead.

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I have done that Chrisso, its just that every time I head out the back of nowhere , my brother turns on the shitty hilux radio and coupled with a 4" long broken rubber ducky antenna, picks up anything and everything, where my high cost gear picks up nuthin'. Not happy and he reminds me every time.

[Winnie]

I got nuffin Phil, sibling rivalry at its finest. My bro and I used to argue over who's captured insect was the toughest. In the end we are all the biggest losers and Spotify is laughing all the way to the bank.

I have added a bullbar mounted GME FM radio whip which was great until I broke it, I hope that helps.

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[Rossco]

Yeah I've just got a whatever brand pillar mount and reckon the GQ gets the best reception in compassion to pretty much everything else I drive around. . . Mind you most work cars have aerials that are half broken lol. . .

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[PeeBee]

New fandangles radio/media player, new ZCG bullbar mount antenna, get as far as Pakenham and things start to fade. I rang the antenna guys and they reckon the issue may be termination on the end of the cable as they supply a pigtail and the end user has to do the soldering. I already has a flying pigtail lead so interchanged the factory supplied push in fitting for a PL259 style cb fitting which should have been fine. They claim those fittings are poor connectors for co-ax, which i simply cannot believe. Anyway, Spotify it is, but no news or weather forecasts. Might clip off the connector and solder it again, not usually something I can stuff up.

OR, I might simply stop going away with him, thats another option I guess.