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Topic: Brake hydro boost on my 1990 foretravel grand villa  (Read 463 times) previous topic - next topic

Brake hydro boost on my 1990 foretravel grand villa

Hya all, sorry ain't been online for a while, been so busy with the boat that, the villa took second fiddle, before I start many thanks to John haygarth and his wife for calling down on boat for coffee when they were over in the UK last year, anyway to the subject in hand, I've just removed my brake booster because of a fluid leak on the pushrod side from brake pedal under the rubber dust boot that goes over rod, I'm pretty confident that I can service and replace all the seals, but I'm not sure on how how to adjust it, once I've fitted it back onto the vehicle, I see there is a clevis and pin that threads onto push rod with a lock nut, so I presume that's where the adjustment is, but it's knowing how to get the adjustment correct, has anyone ever done this job or possibly send me a link on utube or something, I've managed to find several videos on servicing the booster and the seal kit I bought apparently fits all boosters, comes with a variety of seals that will do the job, the booster I have after cross ref from original gm, is a cardone or wagner 52-9902,, i would imagine over the years, this has probably come up as a topic of conversation, but it's finding it that I'm not too good at, there doesn't appear to be any thing in the manuals about adjustment either, any help would be appreciated, thanks kev
1990 foretravel grandvilla, Oshkosh chassis
8.2ltr Detroit turbo

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #1 –
Contact Nitehawk,he just had major problems and repaired it,was just a couple of weeks ago.
96 U270 BUILD 4810
85 380SL
Drummonds TN.

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #2 –
Quote from: John44 –
Contact Nitehawk,he just had major problems and repaired it,was just a couple of weeks ago.
Thanks for that mate, il contact him, thanks ever so mutch
1990 foretravel grandvilla, Oshkosh chassis
8.2ltr Detroit turbo

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #3 –
Sorry, just read this post.
Have you got the Oshkosh Manual pages 556-1  pages 7, 8, 9 & 10 ???
These pages are the only information I have detailing assembly of the powerhead.
I did NOT tear my powerhead apart or even remove it from the coach.
Seems my problem was a 34 year old master cylinder and 34 year old DOT-3 brake fluid. Was really filthy.
Nitehawk,  Demolition Lady, & our NEW master, Zippy the speeding BB cat.
1989 Grand Villa 36' ORED
Oshkosh chassis, 8.2 DD V8
2006 Saturn Vue AWD

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #4 –
Quote from: nitehawk –
Sorry, just read this post.
Have you got the Oshkosh Manual pages 556-1  pages 7, 8, 9 & 10 ???
These pages are the only information I have detailing assembly of the powerhead.
I did NOT tear my powerhead apart or even remove it from the coach.
Seems my problem was a 34 year old master cylinder and 34 year old DOT-3 brake fluid. Was really filthy.
Yes, I have got all the pages you just mentioned and yes they show very clearly how to strip down and reassemble the hydro boost, but connecting back to the brake pedal and doing any adjustments, there doesn't seem to be any mention, so what I've Done is kept the clevis attached to the push rod for now, but when I remove it, I will count the number of turns so I can then replace back in the same position as it was before I took it apart unless I can find something on utube, or unless someone else just happens to see my post that knows what to do,  but thanks anyway  kev
1990 foretravel grandvilla, Oshkosh chassis
8.2ltr Detroit turbo

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #5 –
Try for maybe .8 mm of endplsy when fitted. ?
You need some slack but not too much.

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #6 –
Quote from: Protech Racing –
Try for maybe .8 mm of endplsy when fitted. ?
You need some slack but not too much.

OK I think I understand what you mean, when you say end play, do you mean once it's connected that when I press brake pedal it has to be pushed down . 8mm before it moves the push rod, is that right thanks kev
1990 foretravel grandvilla, Oshkosh chassis
8.2ltr Detroit turbo

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #7 –
Right
It needs to allow the MC to completely release  . So it must have a little gap.  Imho.

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #8 –
Quote from: Protech Racing –
Right
It needs to allow the MC to completely release  . So it must have a little gap.  Imho.
Yeah I understand about the clearence between the master cylinder and the gap between the push rod of the hydro boost when fitted together that all makes sense, the main reason I have took the hydro boost off to service is I have hydraulic fluid leaking very very slowly from the brake pedal side coming from the push rod inside the rubber dust boot, the brakes were working, so as it is at the moment, all I've done is seperated the MC from booster without disturbing anything, even the clevis and pin that attaches to the brake pedal arm I haven't removed yet, I thought as long as I don't disturb anything I should be able to strip it all down replace that seal that is leaking and put it all back together, now correct me if I'm wrong cause I did fit a new MC to it 3 years ago and all I did was take the old MC off and replace with the new one which I bought from Mill supply, but at the time I didn't check the free play because it was just a straight swap, the brakes were working after I had bled the system, but I have never been totally happy with the pressure of the pedal, so I'm wondering maybe i should have checked the free play then,  but I will make sure I do this when I put it back together again, Now, can I do this free play adjustment by rotating the clevis on its thread that attaches to the pedal linkage by turning either clockwise or anticlockwise, or is that adjustment solely for the pedal itself and nothing to do with the freeplay between push rod to MC,  it's a little bit confusing, i keep watching as many videos as I can find on utube which helps,  one other thing is how to remove push rod with the clevis on from the booster, now I managed to find a video last night on how to remove, and all the bloke did was put the booster in a vice so the rod and clevis was pointing downwards and basically he gave the clevis a knock with a hammer from above and the push rod came out of the booster, is that correct with all boosters around 1990 bosch or bendix, I'm not sure what mine is, I'm a bit nervous about doing that just in case there is another way,  cause obviously I don't want to break it and end up having to get a new one, I'm sure there is nothing wrong with the original booster except for the seal, I mean in 33 years the vehicle has only done just over 104,000 miles, thanks kev
1990 foretravel grandvilla, Oshkosh chassis
8.2ltr Detroit turbo

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #9 –
I decided to go up there and take some photos, sometimes it's easier to explain, firstly you can see it looks like a ball joint which makes sense that it just knocks off with a hammer, to replace does it just tap back on,  1 of the photos of the end of hydro boost looks like there is a cover that screws into the body with alignment marks, do I need to take that apart? and also I've took a photo of the number on the side, would this be a bendix or a bosch please
1990 foretravel grandvilla, Oshkosh chassis
8.2ltr Detroit turbo

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #10 –
That is a GM number.


https://www.buyautoparts.com/buynow/1987/Chevrolet/P60/Brake_Booster/73-12227_CPCX?xref=15175818&src=pla&cq_src=google_ads&cq_cmp=812724128&cq_con=146744893110&cq_term=&cq_med=pla&cq_plac=&cq_net=g&cq_pos=&cq_plt=gp&gclid=EAIaIQobChMI5LO9yKqggQMVA3RMCh2vyAvWEAQYBCABEgKWPPD_BwE
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #11 –
Quote from: craneman –
That is a GM number.


https://www.buyautoparts.com/buynow/1987/Chevrolet/P60/Brake_Booster/73-12227_CPCX?xref=15175818&src=pla&cq_src=google_ads&cq_cmp=812724128&cq_con=146744893110&cq_term=&cq_med=pla&cq_plac=&cq_net=g&cq_pos=&cq_plt=gp&gclid=EAIaIQobChMI5LO9yKqggQMVA3RMCh2vyAvWEAQYBCABEgKWPPD_BwE
Yeah that's right, I just was wondering if it's a bendix or bosch
1990 foretravel grandvilla, Oshkosh chassis
8.2ltr Detroit turbo

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #12 –
GM  parts of that year are Bendix.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Brake hydro boost on my 1990 foretravel grand villa

Reply #13 –
Quote from: craneman –
GM  parts of that year are Bendix.
Cheers thanks, also the push rod that goes from pedal to booster, seems to move on a ball joint, saw a video last night, and bloke put booster upside down and whacked the clevis with a hammer and it dropped off, I presume they just push back on,
1990 foretravel grandvilla, Oshkosh chassis
8.2ltr Detroit turbo